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P2085 Exhaust Gas Temperature Sensor Circuit Intermittent Bank 1 Sensor 2
P2085 Exhaust Gas Temperature Sensor Circuit Intermittent Bank 1 Sensor 2 is a generic OBD-II diagnostic trouble code indicating that the Engine Control Module (ECM/PCM) has detected an intermittent electrical signal from the Exhaust Gas Temperature (EGT) sensor circuit on Bank 1 Sensor 2.
In simple terms, the engine computer is receiving an unstable, interrupted, or inconsistent signal from the exhaust temperature sensor.
The EGT sensor monitors exhaust temperature and sends information to the ECM. Depending on the vehicle, this information may be used to control or protect:
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Catalytic converters
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Turbochargers
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Diesel particulate filters (DPF)
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Gasoline particulate filters (GPF)
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Exhaust aftertreatment systems
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EGR systems
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Engine components
When the signal from Bank 1 Sensor 2 intermittently behaves outside the expected electrical parameters, the ECM may store P2085 and illuminate the Check Engine Light.
The exact location and function of Bank 1 Sensor 2 vary by manufacturer. Therefore, the vehicle-specific wiring diagram and service information should always be used to identify the correct sensor.
What Does P2085 Mean?
The code description can be divided into four parts.
Exhaust Gas Temperature Sensor
An Exhaust Gas Temperature sensor measures the temperature of exhaust gases.
Many EGT sensors operate by changing their electrical resistance as exhaust temperature changes. The ECM monitors the circuit and calculates an approximate exhaust temperature from the sensor signal.
The temperature information can then be used for:
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Engine protection
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Turbocharger protection
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Catalytic-converter monitoring
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DPF regeneration
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Exhaust aftertreatment management
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Emissions control
Circuit Intermittent
"Intermittent" means the ECM is detecting a problem that comes and goes rather than remaining continuously present.
For example, the sensor may work normally when the engine is cold but lose its signal when the exhaust becomes hot.
The signal may:
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Drop out
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Suddenly jump
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Become unstable
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Show an implausible temperature
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Lose continuity
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Return to normal
Intermittent faults are frequently caused by wiring, connectors, loose terminals, vibration, or heat-related damage.
Bank 1
Bank 1 refers to the side of a V-type engine that contains cylinder number one.
Therefore:
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Bank 1 = cylinder #1 side
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Bank 2 = opposite side
An inline engine normally has only one cylinder bank.
Sensor 2
Sensor 2 identifies the position of the EGT sensor according to the vehicle manufacturer's sensor configuration.
On many vehicles, Sensor 2 is positioned downstream of the catalytic converter or another major exhaust component.
However, this is not universal.
Turbocharged diesel engines and vehicles with DPF or other aftertreatment systems can have several EGT sensors in different exhaust locations.
Always confirm the exact location using vehicle-specific service information.
How Does an EGT Sensor Work?
A typical EGT system operates as follows:
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Exhaust gases heat the sensor.
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The sensor's electrical resistance or output changes with temperature.
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The ECM monitors the sensor circuit.
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The ECM converts the electrical signal into an estimated exhaust temperature.
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The ECM compares the temperature with expected values.
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The ECM may compare the reading with other EGT sensors.
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The temperature information is used for engine or emissions management.
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If the signal becomes intermittent, the ECM may store P2085.
EGT sensors operate in one of the harshest environments in the vehicle. They are exposed to:
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Extreme heat
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Rapid temperature changes
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Vibration
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Exhaust pressure
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Soot
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Moisture
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Thermal expansion and contraction
These conditions can eventually damage the sensor, connector, or wiring.
Symptoms of P2085
Symptoms depend on the vehicle and how the EGT sensor is used.
Check Engine Light
The Check Engine Light is the most common symptom.
Because the problem is intermittent, the light may sometimes appear after a specific driving condition and disappear after the fault is no longer detected.
Reduced Engine Performance
Some vehicles may activate a protective strategy when the ECM cannot trust exhaust-temperature information.
Possible symptoms include:
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Reduced engine power
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Reduced turbo boost
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Slower acceleration
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Limited engine speed
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Limp mode
Not every vehicle with P2085 will experience reduced performance.
Poor Fuel Economy
Incorrect exhaust-temperature information can affect engine or emissions-control strategies and may increase fuel consumption.
DPF Regeneration Problems
On diesel vehicles, the EGT sensor may be required to monitor exhaust temperature during DPF regeneration.
An intermittent signal can potentially cause:
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Regeneration to be delayed
-
Regeneration to stop
-
Regeneration to fail
-
DPF loading to increase
Turbocharger Protection Problems
Turbocharged engines may use EGT information to help protect the turbocharger from excessive temperatures.
A faulty signal may cause the ECM to reduce boost or activate a protective operating mode.
Increased Emissions
Incorrect EGT information can interfere with emissions-control strategies.
The vehicle may also fail an emissions inspection if the fault remains active.
Abnormal EGT Readings
A scan tool may show:
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Sudden temperature spikes
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Sudden temperature drops
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Implausibly high temperatures
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Implausibly low temperatures
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A temperature reading that disappears
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A temperature that remains fixed
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Unstable temperature values
No Noticeable Symptoms
An intermittent P2085 fault may initially cause only the Check Engine Light.
The vehicle can sometimes drive normally until the wiring or sensor problem becomes more frequent.
Common Causes of P2085
Damaged EGT Sensor Wiring
This is one of the most important possibilities with an intermittent EGT code.
The wiring is exposed to extreme exhaust temperatures.
Possible problems include:
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Melted insulation
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Brittle wires
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Heat damage
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Chafing
-
Broken conductors
-
Wiring stretched or pulled tight
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Harness damage from vibration
A wire can be electrically intact when cold but develop an open circuit when heated.
Loose Electrical Connector
A connector that is not fully secured can intermittently interrupt the sensor signal.
Possible causes include:
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Loose connector
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Damaged locking tab
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Poor terminal tension
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Corrosion
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Water intrusion
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Dirt or debris
Corroded Terminals
Corrosion can increase electrical resistance and cause the EGT signal to fluctuate.
This can occur because of exposure to:
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Moisture
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Road salt
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Water
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Exhaust condensation
Faulty EGT Sensor
The sensor itself may be failing.
Possible sensor problems include:
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Internal electrical failure
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Incorrect resistance
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Signal dropouts
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Temperature drift
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Slow response
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Intermittent operation
Repeated heating and cooling cycles can eventually damage the sensing element.
Heat Damage
Excessive exhaust heat can damage the:
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EGT sensor
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Sensor wiring
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Connector
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Harness insulation
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Nearby electrical components
A wiring harness routed too close to the exhaust can develop an intermittent fault after heat-soaking.
Vibration-Related Wiring Fault
Engine and exhaust-system vibration can cause a partially broken wire or loose terminal to make and lose contact.
The fault may occur only:
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At a particular RPM
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Under acceleration
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On rough roads
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When the engine moves
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When the exhaust system vibrates
Exhaust System Damage
A damaged exhaust component may expose the EGT sensor or harness to abnormal heat or physical stress.
Possible locations include:
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Exhaust manifold
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Turbocharger outlet
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Exhaust pipe
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Catalytic converter
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DPF
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Flex pipe
Poor Previous Wiring Repair
An earlier repair can create an intermittent fault if it used:
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Poor-quality splice
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Incorrect wire
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Loose crimp
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Incorrect connector
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Improper routing
Water or Moisture Intrusion
Water entering the sensor connector can cause intermittent electrical problems.
Sensor Contamination
Depending on the sensor design and location, contamination can affect sensor performance.
Possible contaminants include:
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Soot
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Oil
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Coolant
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Fuel
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Exhaust deposits
Exhaust Temperature Actually Too High
P2085 is an intermittent circuit code, so an actually high exhaust temperature does not automatically mean that the sensor is defective.
However, a genuine excessive exhaust temperature can damage the sensor or wiring and should be investigated if live data confirms abnormal temperatures.
Possible causes include:
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Misfire
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Rich or lean operation
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Incorrect ignition timing
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Incorrect injection timing
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Restricted exhaust
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Turbocharger problems
-
DPF regeneration problems
Engine Misfire
A misfire can allow unburned fuel to enter the exhaust.
This can dramatically increase exhaust temperature and potentially damage:
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EGT sensor
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Catalytic converter
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DPF
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Turbocharger
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Other exhaust components
Fuel Injector Problems
A leaking or incorrectly operating injector can cause abnormal combustion and exhaust temperature.
Incorrect Air-Fuel Mixture
A mixture that is excessively rich or lean can affect exhaust temperature.
Exhaust Restriction
A restricted:
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Catalytic converter
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DPF
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GPF
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Exhaust pipe
can alter exhaust temperature and pressure.
DPF Problems
On diesel vehicles, problems with:
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DPF loading
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Regeneration
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Differential pressure
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Aftertreatment operation
can cause abnormal exhaust temperatures.
Turbocharger Problems
Turbocharger problems can alter exhaust temperature and airflow.
Possible causes include:
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Boost-control faults
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Wastegate problems
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Variable-geometry turbo problems
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Turbocharger damage
ECM/PCM Problem
A problem inside the ECM sensor-input circuit is possible but generally less common than a faulty sensor, connector, or wiring harness.
Software or Calibration Problem
Some vehicles may have manufacturer-specific software or calibration problems that cause incorrect EGT monitoring.
An ECM software update may be available.
Vehicles Commonly Affected by P2085
P2085 can occur on vehicles equipped with multiple EGT sensors and multi-bank exhaust systems.
Examples include:
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Ford F-150
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Ford Super Duty
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Ford Explorer
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Ford Expedition
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Chevrolet Silverado
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Chevrolet Tahoe
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Chevrolet Suburban
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GMC Sierra
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GMC Yukon
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Ram 1500
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Ram 2500
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Ram 3500
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Jeep Grand Cherokee
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Jeep Wrangler
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BMW X5
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BMW X6
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Mercedes-Benz GLE
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Mercedes-Benz G-Class
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Audi Q7
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Volkswagen Touareg
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Porsche Cayenne
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Land Rover Discovery
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Range Rover
This list is not exhaustive.
The exact application of P2085 depends on the vehicle manufacturer, engine, exhaust layout, and emissions-control system.
How Is P2085 Diagnosed?
Because P2085 is an intermittent circuit fault, diagnosis should focus on finding the condition that causes the signal to disappear or become implausible.
The key diagnostic question is:
Is the EGT sensor itself failing, or is the wiring/connector intermittently interrupting the signal?
A third possibility must also be considered:
Is the exhaust temperature actually abnormal?
Step 1: Scan for All Trouble Codes
Use a suitable diagnostic scan tool to retrieve:
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Stored codes
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Pending codes
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History codes
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Manufacturer-specific codes
Look for related codes involving:
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EGT sensors
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DPF
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Catalytic converter
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Exhaust pressure
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Turbocharger
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Fuel system
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Misfire
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Air-fuel mixture
Additional codes can help identify the root cause.
Step 2: Check Freeze-Frame Data
Record the conditions present when P2085 was stored.
Important information includes:
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Engine RPM
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Engine load
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Vehicle speed
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Coolant temperature
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Intake air temperature
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Battery voltage
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EGT temperature
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DPF status
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Regeneration status
Determine whether the fault occurs during:
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Cold start
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Warm-up
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Cruising
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Acceleration
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Heavy engine load
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Deceleration
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DPF regeneration
Step 3: Identify Bank 1 Sensor 2
Do not rely solely on a generic diagram.
Use vehicle-specific service information to identify:
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Exact sensor location
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Connector
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Wiring
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Circuit designation
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Sensor type
This is particularly important on diesel and turbocharged vehicles with multiple EGT sensors.
Step 4: Monitor Live EGT Data
Monitor Bank 1 Sensor 2 using the scan tool.
Look for:
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Sudden temperature jumps
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Sudden drops
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Signal loss
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Fixed temperature
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Implausible temperature
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Unstable readings
Step 5: Compare Other EGT Sensors
If the vehicle has multiple EGT sensors, compare the readings under the same operating conditions.
An unexplained deviation may help identify the faulty sensor.
However, sensors located at different points in the exhaust naturally have different temperatures. Their readings should therefore be compared according to manufacturer specifications rather than assuming they should all show the same value.
Step 6: Inspect the EGT Sensor
Check Bank 1 Sensor 2 for:
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Physical damage
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Burn marks
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Cracks
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Corrosion
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Contamination
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Loose installation
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Damaged sensor wires
Step 7: Inspect the Connector
Check for:
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Corrosion
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Bent pins
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Loose terminals
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Spread terminals
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Backed-out terminals
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Water intrusion
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Melted plastic
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Broken locking tabs
Step 8: Inspect the Wiring Harness
Trace the sensor wiring toward the ECM.
Look for:
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Melted insulation
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Heat damage
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Chafing
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Broken wires
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Pinched wires
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Loose harness clips
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Contact with exhaust components
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Poor previous repairs
Pay particular attention to wiring near:
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Exhaust manifolds
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Turbochargers
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Catalytic converters
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DPFs
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Exhaust pipes
Step 9: Perform a Wiggle Test
Monitor the EGT sensor value while carefully moving the wiring harness and connector.
If the reading suddenly changes or disappears, the harness or connector may have an intermittent fault.
Step 10: Check Sensor Resistance
Depending on the sensor type, measure its resistance at the specified temperature.
Compare the measurement with manufacturer specifications.
Do not use a generic resistance value because EGT sensor characteristics vary between applications.
Step 11: Check Circuit Continuity
Test the wiring for:
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Open circuits
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High resistance
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Short circuits
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Intermittent continuity
Use the manufacturer's wiring diagram.
Step 12: Check Reference or Supply Voltage
Depending on the EGT sensor design, verify the expected reference or supply voltage.
Some EGT sensors use different circuit arrangements, so the correct specification must come from the manufacturer.
Step 13: Check Ground or Return Circuit
Where applicable, verify:
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Ground/return continuity
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Voltage drop
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Circuit integrity
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Connector condition
Step 14: Test the Signal Circuit
Monitor the sensor signal as exhaust temperature changes.
The signal should respond smoothly and consistently.
A sudden electrical change without a corresponding temperature change can indicate a sensor or wiring problem.
Step 15: Check Cold-Start Plausibility
With the engine completely cold, compare the EGT reading with ambient conditions and other temperature sensors.
A major unexplained difference can indicate a sensor or circuit problem.
Step 16: Check for Heat-Related Failure
An intermittent fault may appear only when the exhaust system is hot.
Compare sensor operation:
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When cold
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During warm-up
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After full heat soak
If the signal becomes abnormal only after the sensor and wiring heat up, investigate heat-related sensor or harness damage.
Step 17: Check for Excessive Exhaust Temperature
If the electrical circuit appears healthy, determine whether the exhaust temperature is genuinely too high.
Investigate:
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Misfires
-
Fuel mixture
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Fuel injectors
-
Ignition timing
-
Injection timing
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Turbocharger operation
-
Exhaust restriction
-
DPF regeneration
Step 18: Check DPF and Aftertreatment
On diesel vehicles, inspect:
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DPF loading
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Regeneration status
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Regeneration history
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Differential pressure
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EGT sensor readings
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Related aftertreatment codes
Step 19: Check the Exhaust System
Inspect for:
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Exhaust leaks
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Damaged pipes
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Restricted catalytic converter
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Restricted DPF
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Damaged GPF
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Turbocharger-related exhaust problems
Step 20: Check Manufacturer Service Information
Look for:
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Technical Service Bulletins
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Known EGT sensor failures
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Wiring harness problems
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Connector issues
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Heat-related failures
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ECM software updates
-
Calibration updates
Step 21: Perform Required Adaptation or Relearn
Some vehicles may require an adaptation reset or relearn after replacing an EGT sensor.
Follow the manufacturer-specific procedure.
How to Fix P2085
The correct repair depends on the cause identified during diagnosis.
Repair Damaged EGT Wiring
Repair or replace wiring damaged by:
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Heat
-
Chafing
-
Vibration
-
Corrosion
-
Broken conductors
-
Previous repairs
Ensure the wiring is properly secured and protected from exhaust heat.
Repair or Replace the Connector
If the connector has:
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Corroded terminals
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Loose terminals
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Damaged locking mechanism
-
Melted housing
-
Water intrusion
repair or replace the affected connector components.
Replace the Faulty EGT Sensor
If testing confirms that Bank 1 Sensor 2 is defective, replace it with the correct sensor for the vehicle.
The replacement sensor must have the correct electrical characteristics for the ECM.
Repair Exhaust-System Problems
Repair:
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Exhaust leaks
-
Damaged exhaust components
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Exhaust restrictions
-
DPF problems
-
Catalytic-converter problems
when they are contributing to the fault.
Correct Excessive Exhaust Temperature
If the exhaust is genuinely operating too hot, repair the underlying cause.
Possible causes include:
-
Engine misfire
-
Fuel injector problems
-
Incorrect fuel pressure
-
Rich or lean operation
-
Ignition timing
-
Injection timing
-
Turbocharger problems
-
Exhaust restriction
Repair DPF or Aftertreatment Problems
On applicable diesel vehicles, correct problems involving:
-
DPF regeneration
-
DPF loading
-
Differential pressure
-
Exhaust temperature management
-
Aftertreatment components
Repair Turbocharger Problems
If the turbocharger is responsible for abnormal exhaust conditions, repair the underlying boost or turbocharger fault.
Update or Reprogram the ECM
If manufacturer service information identifies a software or calibration issue, perform the appropriate update.
Replace the ECM/PCM
ECM replacement should generally be the last step.
Before replacing the ECM, verify:
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EGT sensor
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Sensor connector
-
Wiring
-
Reference/supply circuit
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Ground/return circuit
-
Signal circuit
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Circuit resistance
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Continuity
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Exhaust condition
-
Engine operation
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DPF/aftertreatment operation
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Manufacturer software updates
What Happens If P2085 Is Ignored?
Ignoring P2085 may result in:
-
Check Engine Light remaining illuminated
-
Increased emissions
-
Poor fuel economy
-
Reduced engine performance
-
Limp mode on some vehicles
-
DPF regeneration problems
-
Increased DPF loading
-
Aftertreatment problems
-
Incorrect exhaust-temperature monitoring
If the sensor is failing to report a genuinely excessive exhaust temperature, the ECM may not be able to apply the correct protection strategy.
If the exhaust is actually too hot, continued operation can potentially damage:
-
Turbocharger
-
Catalytic converter
-
DPF
-
GPF
-
Other exhaust components
Can You Drive With P2085?
Short-term driving may be possible if the vehicle runs normally and the Check Engine Light is steady, but P2085 should be diagnosed promptly.
Extra caution is appropriate for diesel vehicles where EGT sensors are used for DPF regeneration or aftertreatment management.
Avoid continued driving if the vehicle develops:
-
Severe power loss
-
Limp mode
-
Excessive smoke
-
Strong exhaust smell
-
Abnormal turbocharger noise
-
Severe misfire
-
Overheating
-
Flashing Check Engine Light
-
Other serious warning lights
A flashing Check Engine Light or severe engine-running problem should be treated as an urgent condition.
Is P2085 a Serious Code?
P2085 is generally considered a moderate-severity diagnostic trouble code, but its seriousness depends on the underlying cause.
A loose connector, damaged wire, or failing sensor may be relatively straightforward to repair.
However, if P2085 is associated with:
-
Excessive exhaust temperature
-
DPF restriction
-
Turbocharger problems
-
Severe misfire
-
Fuel-system problems
-
Exhaust aftertreatment failure
the underlying problem may be considerably more serious.
P2085 vs. Related EGT and Camshaft Codes
| Code | General Description |
|---|---|
| P2084 | Exhaust Gas Temperature Sensor Circuit Range/Performance Bank 1 Sensor 2 |
| P2085 | Exhaust Gas Temperature Sensor Circuit Intermittent Bank 1 Sensor 2 |
| P2086 | Exhaust Gas Temperature Sensor Circuit Range/Performance Bank 2 Sensor 2 |
| P2087 | Exhaust Gas Temperature Sensor Circuit Intermittent Bank 2 Sensor 2 |
| P2088 | "A" Camshaft Position Actuator Control Circuit Low Bank 1 |
| P2089 | "A" Camshaft Position Actuator Control Circuit High Bank 1 |
| P2090 | "B" Camshaft Position Actuator Control Circuit Low Bank 1 |
| P2091 | "B" Camshaft Position Actuator Control Circuit High Bank 1 |
Important: Generic OBD-II databases can sometimes contain inconsistent descriptions for neighboring codes. The exact EGT sensor location and circuit designation should always be verified against manufacturer-specific service information.
The key distinction is that P2085 identifies an intermittent electrical problem involving the Bank 1 Sensor 2 EGT circuit, while P2084/P2086 are generally associated with range/performance monitoring.
How to Prevent P2085
Regular maintenance can help reduce the risk of EGT sensor and exhaust-system problems.
Recommended practices include:
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Maintain the engine according to manufacturer recommendations.
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Use the correct engine oil and filters.
-
Maintain the fuel system properly.
-
Repair engine misfires immediately.
-
Repair exhaust leaks promptly.
-
Keep EGT wiring away from excessive heat.
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Ensure exhaust-system wiring is properly secured.
-
Keep electrical connectors clean and dry.
-
Maintain DPF and aftertreatment systems where applicable.
-
Address turbocharger problems promptly.
-
Avoid unauthorized exhaust modifications.
-
Avoid poorly installed tuning modifications.
-
Keep ECM software updated when applicable.
-
Do not ignore recurring Check Engine Light warnings.
Final Thoughts
The P2085 Exhaust Gas Temperature Sensor Circuit Intermittent Bank 1 Sensor 2 diagnostic trouble code indicates that the ECM/PCM has detected an intermittent electrical problem involving the EGT sensor circuit for Bank 1 Sensor 2.
The most likely causes include:
-
Faulty EGT sensor
-
Damaged sensor wiring
-
Heat-damaged wiring insulation
-
Loose connector
-
Corroded terminals
-
Poor terminal tension
-
Partially broken wire
-
Vibration-related wiring problems
-
Water intrusion
-
Poor previous wiring repairs
-
Exhaust-system damage
-
Engine conditions causing abnormal exhaust temperatures
-
ECM/software problems
Because the fault is intermittent, the wiring and connector should receive particular attention. A sensor may function normally during a cold inspection but fail after the exhaust system reaches operating temperature.
The best diagnostic approach is to monitor Bank 1 Sensor 2 live EGT data, inspect the sensor and connector, perform circuit and resistance tests, and use a wiggle test to identify intermittent electrical faults.
If the electrical circuit is healthy, determine whether the exhaust temperature is actually abnormal. Misfires, fuel-system problems, turbocharger faults, exhaust restrictions, and DPF regeneration issues can all contribute to excessive exhaust temperatures.
P2085 should be diagnosed rather than simply cleared, particularly on vehicles where the EGT sensor is used for DPF regeneration, turbocharger protection, catalytic-converter protection, or exhaust aftertreatment control.
