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P2139 Throttle/Pedal Position Sensor/Switch D/F Voltage Correlation
The P2139 Throttle/Pedal Position Sensor/Switch D/F Voltage Correlation diagnostic trouble code indicates that the Engine Control Module (ECM/PCM) has detected that the signals from Throttle/Pedal Position Sensor or Switch circuits D and F are not maintaining the expected relationship.
In simple terms, the vehicle's computer is comparing two position-related electrical signals and has determined that they do not agree with each other within the programmed correlation range.
Modern electronic throttle control systems use multiple position sensors for safety and accuracy. The ECM continuously compares these signals. If the relationship between Sensor D and Sensor F becomes inconsistent, P2139 may be stored.
Depending on the vehicle, this code may cause the Check Engine Light, reduced engine power, poor throttle response, hesitation, limp mode, poor acceleration, rough running, or other electronic throttle control problems.
The exact meaning and physical location of Sensors D and F vary by manufacturer, engine, and vehicle model. The affected sensors may be part of the accelerator pedal assembly, electronic throttle body, or another related throttle-position sensing system.
What Does P2139 Mean?
P2139 means that the ECM/PCM has detected a correlation problem between two position-related sensor signals identified as D and F.
The two sensors do not necessarily produce identical voltages.
Instead, the ECM expects them to follow a specific relationship.
For example:
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One sensor signal may increase as pedal position increases.
-
The second signal may also increase at a different rate.
-
One signal may operate over a different voltage range.
-
One signal may decrease while the other increases.
As long as the signals maintain the manufacturer's expected relationship, the system operates normally.
If one signal becomes:
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Too high
-
Too low
-
Intermittent
-
Frozen
-
Erratic
-
Delayed
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Outside the expected correlation range
the ECM may store P2139.
Why Does the Vehicle Use Multiple Position Sensors?
Electronic throttle systems use redundancy for safety.
Many modern vehicles do not use a traditional mechanical throttle cable.
Instead:
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The driver presses the accelerator pedal.
-
Electronic position sensors detect pedal movement.
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The ECM compares the sensor signals.
-
The ECM calculates the requested engine power.
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The ECM commands the electronic throttle body.
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Throttle position sensors report the actual throttle opening.
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The ECM compares the expected and actual positions.
Using multiple sensors allows the ECM to identify sensor faults before they create unsafe throttle behavior.
What Does "Voltage Correlation" Mean?
A voltage correlation code means that the relationship between two sensor signals is incorrect.
It does not necessarily mean that both signals are simply high or low.
For example, as the accelerator pedal moves:
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Sensor D should follow its programmed voltage pattern.
-
Sensor F should follow its own programmed voltage pattern.
The ECM compares them continuously.
A correlation fault may occur when:
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One signal increases but the other does not.
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One signal suddenly drops out.
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One signal becomes erratic.
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The difference between signals becomes too large.
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One sensor remains fixed.
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One signal changes more slowly than expected.
Where Are Sensors D and F Located?
The exact location depends on the vehicle.
The sensors may be:
Inside the accelerator pedal assembly
Modern accelerator pedals often contain multiple position sensors.
Inside the electronic throttle body
The throttle body may contain multiple throttle position sensors.
Part of another electronically controlled throttle or air-management system
The exact D/F circuit identification should always be confirmed using manufacturer service information.
Do not assume that Sensor D and Sensor F are located in the same physical component.
Symptoms of P2139
Symptoms vary depending on the vehicle and the severity of the sensor disagreement.
Check Engine Light
The Check Engine Light is the most common symptom.
Reduced Engine Power
Many vehicles enter a protective reduced-power mode.
Poor Throttle Response
The vehicle may respond slowly to accelerator pedal input.
Poor Acceleration
Acceleration may be significantly reduced.
Limp Mode
The ECM may limit throttle opening to prevent incorrect throttle operation.
Engine Hesitation
The vehicle may hesitate during acceleration.
Inconsistent Acceleration
Engine response may feel irregular.
Engine Surging
The engine may experience inconsistent throttle response.
Rough Idle
Idle quality may be affected in some vehicles.
Engine Stalling
Severe throttle-control faults can contribute to stalling.
Cruise Control Problems
Cruise control may be disabled.
Additional Warning Messages
The vehicle may display messages such as:
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Reduced engine power
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Service throttle system
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Electronic throttle control fault
-
Engine fault
-
Drive system fault
Common Causes of P2139
Faulty Accelerator Pedal Position Sensor
Many accelerator pedals contain multiple internal sensors.
If one signal no longer matches another signal, P2139 may be stored.
Possible failures include:
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Internal sensor wear
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Electrical failure
-
Contamination
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Incorrect internal resistance
-
Signal dropout
On many vehicles, the complete accelerator pedal assembly must be replaced.
Faulty Electronic Throttle Body
The electronic throttle body may contain:
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Throttle position sensors
-
Throttle actuator motor
-
Internal electronics
An internal position-sensor disagreement can cause a correlation code.
Possible problems include:
-
Internal sensor failure
-
Actuator failure
-
Internal electrical fault
-
Incorrect position feedback
Damaged Wiring
Damaged wiring can affect one sensor signal while another continues operating.
Possible causes include:
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Chafed wiring
-
Broken wire
-
Melted insulation
-
Heat damage
-
Corrosion
-
Engine vibration
-
Previous repair damage
Corroded Electrical Connectors
Corrosion can cause unstable sensor readings.
Look for:
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Green corrosion
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White deposits
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Moisture
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Oxidized terminals
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Loose pins
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Damaged connector housing
Loose or Damaged Terminals
A connector may appear properly connected while an internal terminal is:
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Loose
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Bent
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Corroded
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Backed out
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Partially disconnected
This can cause intermittent sensor correlation faults.
Short to Ground
A sensor signal wire may contact:
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Chassis ground
-
Engine metal
-
Another ground circuit
This can pull the signal voltage down and cause the two sensors to disagree.
Short to Power
A sensor signal wire may contact:
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Battery voltage
-
Ignition power
-
Another positive voltage circuit
This can force one sensor signal too high.
Open Circuit
A broken or disconnected wire can interrupt one sensor signal.
Possible causes include:
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Broken wire
-
Damaged connector
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Failed splice
-
Internal harness damage
Reference-Voltage Problems
Many position sensors use a regulated reference voltage.
A problem with the reference-voltage circuit can affect sensor operation.
Possible causes include:
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Shorted sensor
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Damaged reference-voltage wire
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Wiring problem
-
Faulty ECM/PCM circuit
Poor Sensor Ground
A poor sensor ground can change the voltage reported to the ECM.
Possible causes include:
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Corroded ground wiring
-
Loose connector
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Damaged sensor ground
-
ECM/PCM ground problem
Low Battery or Charging-System Voltage
Low system voltage can affect electronic throttle operation.
Possible causes include:
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Weak battery
-
Faulty alternator
-
Poor battery terminals
-
Charging-system wiring problems
-
Poor engine grounds
Throttle Plate Contamination
Carbon buildup can interfere with throttle movement.
Possible symptoms include:
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Sticking throttle plate
-
Rough idle
-
Poor acceleration
-
Reduced engine response
However, contamination alone does not normally explain an electrical voltage correlation code unless mechanical sticking causes abnormal position feedback.
Mechanical Throttle Binding
The throttle plate may not move correctly because of:
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Carbon buildup
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Mechanical damage
-
Debris
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Damaged throttle shaft
This may create a difference between expected and actual throttle position.
Incorrect Previous Repairs
A previous repair may have caused:
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Incorrect wiring connection
-
Damaged wire
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Poor splice
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Incorrect connector installation
-
Pinched wiring
Aftermarket Modifications
Possible sources of interference include:
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ECU tuning
-
Pedal controllers
-
Throttle-response devices
-
Engine swaps
-
Modified wiring harnesses
-
Aftermarket engine electronics
Faulty ECM/PCM
An ECM/PCM problem is possible but less common than:
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Sensor failure
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Throttle body failure
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Pedal assembly failure
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Wiring damage
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Connector problems
-
Reference-voltage faults
The ECM/PCM should only be considered after external circuits are properly tested.
Vehicles Commonly Affected by P2139
P2139 can occur on many OBD-II vehicles equipped with electronic throttle control systems.
Examples may include:
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Ford F-150
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Ford Explorer
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Ford Mustang
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Ford Focus
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Ford Ranger
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Chevrolet Silverado
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Chevrolet Tahoe
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Chevrolet Malibu
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Chevrolet Camaro
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GMC Sierra
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GMC Yukon
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Cadillac Escalade
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Dodge Charger
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Dodge Challenger
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Ram 1500
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Jeep Grand Cherokee
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Jeep Wrangler
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Chrysler Pacifica
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Toyota Camry
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Toyota Tundra
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Toyota Tacoma
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Honda Accord
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Honda Civic
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Honda CR-V
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Nissan Altima
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Nissan Pathfinder
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Nissan Titan
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BMW 3 Series
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BMW 5 Series
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Mercedes-Benz C-Class
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Mercedes-Benz E-Class
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Volkswagen Golf
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Volkswagen Passat
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Audi A4
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Audi A6
This list is not exhaustive.
P2139 is more likely to occur on vehicles using electronic throttle control with multiple redundant position sensors.
How Is P2139 Diagnosed?
The purpose of diagnosis is to determine which signals are identified as D and F on the specific vehicle and why they are no longer correlating correctly.
Check for Additional Trouble Codes
Perform a complete diagnostic scan.
Look for:
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P2139
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P2140
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Other throttle position codes
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Accelerator pedal position codes
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Throttle actuator codes
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5-volt reference codes
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Battery-voltage codes
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Communication codes
Related codes can help identify the source of the problem.
Check Freeze-Frame Data
Review the conditions recorded when P2139 was stored.
Useful information includes:
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Engine RPM
-
Vehicle speed
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Engine load
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Battery voltage
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Accelerator pedal position
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Throttle position
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Coolant temperature
This can help determine when the correlation failure occurs.
Identify Sensors D and F
This is one of the most important diagnostic steps.
Use manufacturer service information to determine:
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The component associated with Sensor D
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The component associated with Sensor F
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Their expected voltage ranges
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Their expected relationship
-
Relevant ECM/PCM terminals
Do not assume that D and F have the same meaning on every vehicle.
Monitor Live Data
Use a capable scan tool to monitor:
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Throttle position
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Accelerator pedal position
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Sensor D signal
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Sensor F signal
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Commanded throttle position
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Actual throttle position
Slowly operate the accelerator pedal and observe the data.
The signals should:
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Change smoothly
-
Remain stable
-
Maintain the expected relationship
Look for:
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Dropouts
-
Sudden jumps
-
Frozen readings
-
Erratic changes
-
One signal changing while the other remains fixed
Check Battery and Charging Voltage
Verify:
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Battery condition
-
Battery terminals
-
Alternator operation
-
Charging voltage
-
Engine and chassis grounds
Repair system-voltage problems before continuing with detailed sensor diagnosis.
Inspect the Accelerator Pedal Connector
Check for:
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Corrosion
-
Loose terminals
-
Bent pins
-
Water intrusion
-
Damaged locking tabs
-
Backed-out terminals
Inspect the Throttle Body Connector
Check for:
-
Corrosion
-
Heat damage
-
Loose terminals
-
Broken wiring
-
Oil contamination
Inspect Wiring Harnesses
Inspect wiring between:
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Accelerator pedal and ECM
-
Throttle body and ECM
-
Sensor circuits and ECM/PCM
Look for:
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Chafing
-
Broken insulation
-
Melted wiring
-
Exposed conductors
-
Previous repairs
-
Pinched harnesses
Check Reference Voltage
Measure the relevant reference voltage according to manufacturer procedures.
Many systems use approximately a 5-volt reference.
Check:
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Reference voltage
-
Sensor ground
-
Sensor output
-
Wiring continuity
Check for Short Circuits
Inspect for:
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Short to ground
-
Short to power
-
Short between sensor wires
-
Internal component short
A short can cause one signal to move outside the expected D/F relationship.
Perform Voltage-Drop Testing
Voltage-drop testing can help locate excessive resistance in:
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Power circuits
-
Ground circuits
-
Connector terminals
-
Splices
Test the Accelerator Pedal Assembly
If the affected D/F circuits are located in the accelerator pedal assembly, test the internal sensors according to manufacturer specifications.
If one sensor fails, the complete pedal assembly may require replacement.
Test the Electronic Throttle Body
If the affected circuits are located in the throttle body, test:
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Power supply
-
Ground
-
Throttle position sensors
-
Actuator motor
-
Position feedback
Compare all results with manufacturer specifications.
Inspect the Throttle Plate
If electrical tests are normal, inspect the throttle body for:
-
Carbon buildup
-
Mechanical sticking
-
Damaged throttle plate
-
Restricted movement
Check for Aftermarket Modifications
Inspect:
-
Pedal controllers
-
ECU tuning
-
Throttle-response devices
-
Modified wiring
-
Engine swaps
Incorrect modifications can affect sensor correlation.
Check ECM/PCM Power and Grounds
Verify:
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Battery power
-
Ignition power
-
ECM/PCM grounds
-
Sensor reference circuits
How to Fix P2139
The correct repair depends on the cause identified during diagnosis.
Replace a Faulty Accelerator Pedal Assembly
If the pedal position sensors are internally defective, replacement of the complete pedal assembly may restore correct correlation.
Replace a Faulty Electronic Throttle Body
If testing confirms internal throttle sensor or actuator failure, replace the throttle body or applicable component.
Repair Damaged Wiring
Repair or replace wiring damaged by:
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Heat
-
Chafing
-
Corrosion
-
Vibration
-
Previous repairs
Repair or Replace Damaged Connectors
Replace damaged connector housings or terminals and ensure correct terminal tension.
Repair Reference-Voltage Problems
Repair damaged:
-
Reference-voltage wiring
-
Sensor ground circuits
-
Related sensor circuits
Repair Power and Ground Problems
Restore proper:
-
Battery connections
-
Engine grounds
-
Chassis grounds
-
ECM/PCM grounds
-
Throttle actuator power circuits
Repair Short Circuits
Locate and repair wires shorted to:
-
Ground
-
Battery voltage
-
Another electrical circuit
Clean the Throttle Body
If carbon buildup is affecting throttle movement, clean the throttle body according to manufacturer procedures.
Avoid damaging electronic sensors and actuator components.
Correct Previous Repairs
Restore the original wiring configuration when previous repairs caused the fault.
Correct Aftermarket Modifications
Restore the throttle-control system to the correct manufacturer configuration when modifications are responsible.
Perform Required Relearn Procedures
Some vehicles may require:
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Throttle body relearn
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Idle relearn
-
Accelerator pedal calibration
-
Electronic throttle adaptation
Use the correct manufacturer procedure.
Repair or Replace the ECM/PCM
The ECM/PCM should only be considered after all sensors, wiring, connectors, power supplies, grounds, and reference circuits have been properly tested.
What Happens If P2139 Is Ignored?
Ignoring P2139 can cause continuing throttle-control problems.
Possible consequences include:
-
Reduced engine power
-
Poor acceleration
-
Limp mode
-
Engine hesitation
-
Rough running
-
Engine stalling
-
Poor fuel economy
-
Additional throttle-control codes
-
Increased emissions
Because sensor correlation is an important safety function, the code should not be ignored.
Can You Drive With P2139?
Driving with P2139 may be possible, but the vehicle should be diagnosed promptly.
A short drive may be possible if:
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The engine runs smoothly.
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Throttle response remains predictable.
-
There is no major loss of power.
-
The vehicle is not stalling.
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The Check Engine Light is not flashing.
Avoid driving if you experience:
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Sudden power loss
-
Severe reduction in engine power
-
Repeated stalling
-
Unpredictable throttle response
-
Severe hesitation
-
Flashing Check Engine Light
-
Multiple warning messages
Is P2139 a Serious Code?
P2139 is generally considered a moderate to potentially high-severity diagnostic trouble code.
Modern electronic throttle systems use redundant sensor signals for safety.
When the ECM detects that two position signals no longer correlate correctly, it may reduce engine power to prevent incorrect throttle operation.
The fault can affect:
-
Throttle response
-
Engine power
-
Acceleration
-
Driveability
-
Fuel efficiency
The vehicle should be diagnosed promptly, especially if reduced-power mode is active.
How to Prevent P2139
Recommended practices include:
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Keep electrical connectors clean and dry.
-
Repair damaged wiring promptly.
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Secure wiring harnesses correctly.
-
Maintain battery terminals.
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Maintain engine and chassis grounds.
-
Address charging-system problems quickly.
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Keep the throttle body clean when appropriate.
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Avoid poorly designed throttle modifications.
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Avoid low-quality electrical repairs.
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Inspect wiring after major engine repairs.
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Use correct replacement parts.
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Do not ignore Check Engine Light warnings.
P2139 vs. Related Codes
| Code | General Description |
|---|---|
| P2139 | Throttle/Pedal Position Sensor/Switch D/F Voltage Correlation |
| P2140 | Throttle/Pedal Position Sensor/Switch E/F Voltage Correlation |
| P2138 | Throttle/Pedal Position Sensor/Switch D/E Voltage Correlation |
| P2137 | Throttle/Pedal Position Sensor/Switch C/E Voltage Correlation |
| P2136 | Throttle/Pedal Position Sensor/Switch C/D Voltage Correlation |
| P2135 | Throttle/Pedal Position Sensor/Switch A/B Voltage Correlation |
The main difference is the specific sensor pair being compared.
P2139 relates specifically to the expected relationship between Sensor D and Sensor F.
Final Thoughts
The P2139 Throttle/Pedal Position Sensor/Switch D/F Voltage Correlation diagnostic trouble code indicates that the ECM/PCM has detected that two position-related signals identified as D and F are no longer maintaining their expected electrical relationship.
Common causes include:
-
Faulty accelerator pedal position sensor
-
Faulty electronic throttle body
-
Internal sensor failure
-
Damaged wiring
-
Corroded connectors
-
Loose terminals
-
Short circuits
-
Open circuits
-
Reference-voltage problems
-
Poor sensor grounds
-
Low system voltage
-
Throttle plate contamination
-
Mechanical throttle binding
-
Incorrect previous repairs
-
Aftermarket modifications
-
ECM/PCM faults
Correct diagnosis begins by identifying what Sensors D and F represent on the specific vehicle.
A capable scan tool should then be used to compare the sensor signals in live data while the accelerator pedal and throttle position change.
The wiring, connectors, power supply, sensor grounds, and reference-voltage circuits should also be tested before replacing expensive components.
P2139 does not automatically mean that the accelerator pedal assembly or throttle body must be replaced. Wiring damage, a corroded connector, poor sensor ground, reference-voltage fault, or another electrical problem can produce the same correlation code.
Finding the exact reason why the D and F signals no longer agree is essential for restoring safe throttle operation, reliable engine performance, and proper vehicle driveability.
