P2489 Exhaust Gas Temperature Sensor Circuit Intermittent/Erratic Bank 2 Sensor 5

P2489 is a generic OBD-II diagnostic trouble code that indicates the Engine Control Module (ECM) has detected an intermittent or erratic signal from the Exhaust Gas Temperature (EGT) Sensor located at Bank 2 Sensor 5. Unlike an open, low, high, or range/performance fault, this code means the sensor signal is unstable, appearing and disappearing or fluctuating unexpectedly while the engine is operating.

The ECM continuously monitors exhaust gas temperatures to control emission systems and protect components such as the Diesel Particulate Filter (DPF), catalytic converter, turbocharger, and Selective Catalytic Reduction (SCR) system. When the signal from Bank 2 Sensor 5 becomes inconsistent, the ECM stores code P2489 and illuminates the Check Engine Light.

Although the vehicle may continue to operate normally at first, an intermittent sensor signal can prevent proper emission system operation and eventually lead to additional fault codes.

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What Does P2489 Mean?

Modern diesel engines and many turbocharged gasoline engines use several Exhaust Gas Temperature sensors installed throughout the exhaust system.

These sensors monitor temperatures before and after components including:

• Turbocharger

• Diesel Oxidation Catalyst (DOC)

• Diesel Particulate Filter (DPF)

• SCR catalyst

• Catalytic converter

Bank 2 refers to the side of the engine opposite Cylinder 1 on V-type engines.

Sensor 5 is generally positioned toward the downstream section of the exhaust system. Depending on the vehicle, it may be installed after the SCR catalyst or near the rear portion of the emission control system.

The ECM expects the sensor signal to change smoothly as exhaust temperatures rise and fall. If the signal suddenly drops out, spikes unexpectedly, or fluctuates without matching actual operating conditions, diagnostic code P2489 is stored.

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Common Symptoms of P2489

The symptoms often appear intermittently because the electrical fault itself is usually intermittent.

Common symptoms include:

• Check Engine Light illuminated

• Malfunction Indicator Lamp (MIL) on

• Intermittent loss of engine performance

• Occasional limp mode activation

• Interrupted DPF regeneration

• Increased exhaust emissions

• Reduced fuel economy

• Emission system warning messages

• Failed emissions inspection

• Additional emission-related trouble codes

• Intermittent warning lights that may disappear and return

Some drivers may notice no performance problems other than the Check Engine Light.

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Common Causes of P2489

Intermittent faults are usually more difficult to diagnose because the problem may not be present during inspection.

Failing exhaust gas temperature sensor

An aging sensor may produce unstable signals as internal electrical components deteriorate.

Loose electrical connector

A connector that is not fully seated can cause the signal to disconnect momentarily due to engine vibration.

Corroded connector terminals

Corrosion may create intermittent electrical contact.

Damaged wiring harness

The wiring may suffer from:

• Heat damage

• Melted insulation

• Chafing

• Broken wire strands

• Vibration fatigue

Intermittent open circuit

A partially broken wire may make contact only under certain driving conditions.

Poor ground connection

An unstable ground can cause the sensor signal to fluctuate.

Water intrusion

Moisture inside the connector may create temporary electrical interruptions.

Exhaust system vibration

Loose exhaust components may place excessive stress on the sensor wiring and connectors.

ECM electrical fault

Although uncommon, an internal ECM problem may occasionally interrupt sensor communication.

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Vehicles Commonly Affected by P2489

P2489 is most commonly found on diesel vehicles equipped with advanced emission control systems.

Frequently affected vehicles include:

• Ford F-Series Power Stroke

• Ford Transit Diesel

• Chevrolet Silverado Duramax

• GMC Sierra Duramax

• Ram 2500 Cummins

• Ram 3500 Cummins

• Mercedes-Benz Sprinter

• Mercedes-Benz GLE Diesel

• BMW X5 Diesel

• BMW X3 Diesel

• Audi Q7 TDI

• Volkswagen Touareg TDI

• Volkswagen Amarok

• Land Rover Discovery

• Range Rover Sport Diesel

• Jeep Grand Cherokee EcoDiesel

• Nissan Navara

• Toyota Land Cruiser Diesel

• Isuzu D-Max

• Mitsubishi L200

Some turbocharged gasoline engines equipped with multiple exhaust gas temperature sensors may also experience this code.

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How Is P2489 Diagnosed?

Intermittent electrical faults require careful testing because the problem may not occur continuously.

Check for additional diagnostic trouble codes

Related codes involving:

• Other EGT sensors

• DPF system

• SCR system

• NOx sensors

• Oxygen sensors

may help identify the source of the fault.

Inspect the wiring harness

The technician should inspect for:

• Burned insulation

• Melted wiring

• Chafed sections

• Loose routing clips

• Broken conductors

Special attention should be paid to areas exposed to high exhaust temperatures.

Inspect the connector

The connector should be checked for:

• Loose locking tabs

• Bent terminals

• Corrosion

• Moisture

• Damaged pins

Perform a wiggle test

While monitoring live scan data, technicians gently move the wiring harness and connector. If the temperature reading suddenly changes or disappears, an intermittent wiring fault is likely present.

Review live scan data

A professional scan tool can compare all exhaust gas temperature sensors.

A faulty Sensor 5 may display:

• Random temperature spikes

• Sudden temperature drops

• Signal loss

• Unstable readings compared with nearby sensors

Measure circuit continuity

Continuity and resistance testing help identify partially broken wires that may only fail under vibration.

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How to Fix P2489

The appropriate repair depends on the source of the intermittent signal.

Common repairs include:

• Replacing the faulty exhaust gas temperature sensor

• Repairing damaged wiring

• Replacing worn wiring harnesses

• Cleaning corroded electrical connectors

• Tightening loose electrical connections

• Replacing damaged connector terminals

• Repairing poor ground connections

• Securing the wiring harness away from hot exhaust components

• Updating ECM software if recommended by the manufacturer

• Replacing the ECM if an internal fault is confirmed

After repairs, the fault code should be cleared and the vehicle should be driven under normal operating conditions to verify that the intermittent fault has been eliminated.

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Can You Drive With P2489?

The vehicle will often remain drivable, but continuing to drive without repairing the problem is not recommended.

An unstable exhaust temperature signal can interfere with proper operation of the emission control system and may lead to:

• Disabled DPF regeneration

• Increased soot accumulation

• Reduced engine performance

• Limp mode activation

• Increased emissions

• Additional diagnostic trouble codes

If the vehicle frequently enters limp mode or repeatedly displays emission system warnings, repairs should be performed as soon as possible.

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Is P2489 a Serious Code?

Yes. P2489 is considered a moderately serious diagnostic trouble code.

Although it rarely causes immediate engine damage, an intermittent exhaust temperature sensor signal can eventually contribute to:

• Diesel Particulate Filter blockage

• SCR system performance issues

• Increased emissions

• Reduced engine efficiency

• Catalytic converter stress

• Additional exhaust aftertreatment faults

Early diagnosis prevents intermittent electrical faults from developing into more expensive emission system repairs.

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How to Prevent P2489

Routine inspection of the exhaust wiring and emission system helps reduce the likelihood of intermittent sensor faults.

Recommended preventive maintenance includes:

• Inspect exhaust wiring during routine servicing.

• Replace damaged heat shields promptly.

• Secure wiring away from hot exhaust components.

• Repair damaged insulation immediately.

• Clean electrical connectors if corrosion is present.

• Ensure connectors are fully locked after service.

• Repair exhaust leaks that expose wiring to excessive heat.

• Investigate intermittent Check Engine Lights without delay.

Regular maintenance of the exhaust sensor wiring and connectors helps ensure reliable exhaust temperature monitoring and proper operation of the vehicle's emission control system.

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Final Thoughts

P2489 Exhaust Gas Temperature Sensor Circuit Intermittent/Erratic Bank 2 Sensor 5 indicates that the ECM is receiving an unstable or inconsistent signal from the fifth exhaust gas temperature sensor on Bank 2. The most common causes include a failing sensor, loose or corroded connectors, damaged wiring, intermittent open circuits, poor ground connections, or vibration-related electrical faults. Because accurate exhaust temperature data is essential for controlling the DPF, SCR system, catalytic converter, and turbocharger, this code should not be ignored.

Identifying and repairing the underlying intermittent electrical problem restores reliable exhaust temperature monitoring, improves emission system performance, prevents unnecessary limp mode activation, and helps protect expensive exhaust aftertreatment components from long-term damage.