Faulty throttle position sensor (TPS) or accelerator pedal position (APP) sensor 'D' or 'F'; Corroded, damaged, or loose wiring or connectors in the sensor 'D' or 'F' circuit; Mechanical binding or carbon buildup in the throttle body causing sensor signal mismatch; A short or open in the sensor reference voltage or ground circuit shared by sensors 'D' and 'F'; Failed or failing PCM, though this is rare and should be diagnosed last; Aftermarket electronic throttle controllers or pedal tuners interfering with sensor signals; Water intrusion or contamination inside the sensor or connector housing

DTC codes / P21xx · Fuel and air metering / P2139

P2139Throttle/Pedal Position Sensor/Switch 'D' / 'F' Voltage Correlation

P2139 is set when the engine computer compares the voltage signals from throttle or pedal position sensors 'D' and 'F' and finds they do not agree within the expected margin for a calibrated period of time. The computer has detected a correlation error between two redundant sensor circuits that should track each other closely, indicating a wiring, sensor, or mechanical fault in the throttle body or accelerator pedal assembly.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Reduced engine power or limp mode, where the throttle responds sluggishly or not at all
Unstable or surging idle, or the engine may stall when coming to a stop
Poor acceleration or a hesitation when pressing the accelerator pedal
A stored code in the powertrain control module (PCM) with possible freeze-frame data showing the voltage mismatch
On some vehicles, the electronic throttle control (ETC) system may default to a fixed idle speed

Common causes, most likely first

Faulty throttle position sensor (TPS) or accelerator pedal position (APP) sensor 'D' or 'F'
Corroded, damaged, or loose wiring or connectors in the sensor 'D' or 'F' circuit
Mechanical binding or carbon buildup in the throttle body causing sensor signal mismatch
A short or open in the sensor reference voltage or ground circuit shared by sensors 'D' and 'F'
Failed or failing PCM, though this is rare and should be diagnosed last
Aftermarket electronic throttle controllers or pedal tuners interfering with sensor signals
Water intrusion or contamination inside the sensor or connector housing

How to diagnose and fix it

Scan all modules for stored and pending codes, and record freeze-frame data to see when the fault occurred
Visually inspect the throttle body and accelerator pedal sensor connectors for corrosion, loose pins, or damaged wires
Check the sensor reference voltage and ground circuits with a digital multimeter (DMM) to ensure they are within specification
Back-probe the 'D' and 'F' sensor signal wires and compare their voltages while slowly moving the throttle or pedal through its range
Clean the throttle body and perform a throttle relearn or calibration procedure if the vehicle requires it
Replace the faulty sensor or sensor assembly if voltage correlation tests confirm an internal failure
Clear codes and perform a road test to verify the repair and ensure the code does not return

What a voltage correlation code really means

P2139 is often set by a mechanical issue in the throttle body, such as carbon buildup or a sticking plate, rather than a failed sensor, so cleaning and recalibration can resolve it without parts replacement.
The code compares two redundant sensors that should mirror each other; a single sensor can drift slightly without setting a code until the mismatch exceeds a calibrated threshold over time.
Aftermarket throttle controllers or pedal tuners that modify sensor signals are a common cause of correlation codes and should be removed before diagnosis.
A weak battery or poor charging system can cause erratic sensor voltages and set correlation codes, so always verify battery and charging system health first.
The PCM may not illuminate the check engine light immediately; the code can be stored pending and only mature to a confirmed code after multiple drive cycles.

Can I keep driving with P2139?

If the vehicle is in limp mode or the throttle response is unpredictable, avoid driving and have it towed to a repair shop. If the only symptom is a warning light and the car drives normally, you can drive cautiously to a workshop, but avoid heavy acceleration or high speeds until the fault is repaired.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.