Faulty throttle position sensor or switch G (accelerator pedal position sensor); Damaged or corroded wiring in the sensor's signal circuit; Poor electrical connection at the sensor or ECM connector; Short to ground in the signal circuit; Failed ECM (less common)

DTC codes / P21xx · Fuel and air metering / P212C

P212CThrottle Position Sensor/Switch G Circuit Low

Q: What does code P212C mean?

Throttle Position Sensor/Switch G Circuit Low. P212C indicates that the engine control module (ECM) has detected a low voltage condition on the signal circuit of throttle position sensor or switch G. This sensor is part of the accelerator pedal position system, and the ECM expects a specific voltage range that corresponds to the pedal's position; a low voltage means the signal is below the expected threshold, which can affect throttle control.

P212C indicates that the engine control module (ECM) has detected a low voltage condition on the signal circuit of throttle position sensor or switch G. This sensor is part of the accelerator pedal position system, and the ECM expects a specific voltage range that corresponds to the pedal's position; a low voltage means the signal is below the expected threshold, which can affect throttle control.

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, limiting vehicle speed
Poor acceleration or hesitation when pressing the accelerator pedal
Unresponsive or erratic throttle behavior
In some cases, the engine may stall or idle poorly

Common causes, most likely first

Faulty throttle position sensor or switch G (accelerator pedal position sensor)
Damaged or corroded wiring in the sensor's signal circuit
Poor electrical connection at the sensor or ECM connector
Short to ground in the signal circuit
Failed ECM (less common)

How to diagnose and fix it

Use an OBD-II scanner to confirm the code and check for related codes in the accelerator pedal position system
Visually inspect the sensor and its wiring for damage, corrosion, or loose connections
Measure the sensor's signal voltage with a multimeter and compare to manufacturer specifications
Check the signal circuit for a short to ground using a wiring diagram and multimeter
If the sensor is faulty, replace it and clear the code
If wiring is damaged, repair or replace the affected section
After repairs, clear codes and perform a road test to verify the fix

Common Missteps When Diagnosing P212C

A low voltage code on sensor G often results from a poor ground connection rather than a failed sensor, so always check ground points before replacing parts.
The accelerator pedal position sensor may have multiple circuits; a low voltage on one circuit can be caused by a short to ground in a different circuit, so inspect the entire harness.
Some vehicles use a single assembly for multiple pedal sensors; replacing just one sensor may not be possible, requiring replacement of the whole pedal assembly.
Intermittent connections can set this code without permanent failure; wiggle-test the harness while monitoring live data to catch intermittent faults.
After replacing the sensor, a relearn or calibration procedure may be required for the ECM to recognize the new sensor's voltage range.

Can I keep driving with P212C?

If the vehicle enters limp mode or exhibits severe power loss, avoid driving until repaired. If the only symptom is the check engine light, you may drive cautiously to a repair shop, but be prepared for sudden throttle response changes.

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.