Faulty idle signal circuit wiring (open, short to ground, or short to voltage); Dirty or failing electronic throttle body (carbon buildup on the throttle plate); Defective accelerator pedal position sensor or idle signal switch; Poor electrical connection at the throttle body or pedal connector; Failed throttle actuator control module or PCM; Aftermarket electronic accessories improperly wired into the idle circuit

DTC codes / GM codes / P1510

P1510 · GMIdle Signal Circuit Malfunction

Q: What does code P1510 mean?

Idle Signal Circuit Malfunction. P1510 on GM vehicles indicates the powertrain control module (PCM) has detected an abnormal voltage condition on the idle signal circuit, which is used by the throttle actuator control (TAC) system to monitor idle requests. The PCM expects a specific voltage range from the idle signal circuit and sets this code when the signal is out of range, stuck, or intermittent.

P1510 on GM vehicles indicates the powertrain control module (PCM) has detected an abnormal voltage condition on the idle signal circuit, which is used by the throttle actuator control (TAC) system to monitor idle requests. The PCM expects a specific voltage range from the idle signal circuit and sets this code when the signal is out of range, stuck, or intermittent.

SystemPowertrain

Code typeGM specific

SeverityMedium

Fix difficultyIntermediate

AreaVehicle speed, idle control and auxiliary inputs

Symptoms you may notice

Illuminated check engine light, often with no other noticeable symptoms
Unstable or fluctuating idle speed
Idle speed stuck too high or too low
Engine may stall when coming to a stop
Reduced engine power message or limp mode in some cases
Poor throttle response at low speeds

Common causes, most likely first

Faulty idle signal circuit wiring (open, short to ground, or short to voltage)
Dirty or failing electronic throttle body (carbon buildup on the throttle plate)
Defective accelerator pedal position sensor or idle signal switch
Poor electrical connection at the throttle body or pedal connector
Failed throttle actuator control module or PCM
Aftermarket electronic accessories improperly wired into the idle circuit

How to diagnose and fix it

Inspect the throttle body and clean carbon deposits from the throttle plate and bore
Check the idle signal circuit wiring for damage, corrosion, or loose connectors
Measure voltage and resistance on the idle signal circuit according to GM service information
Test the accelerator pedal position sensor and idle signal switch for proper operation
Perform a throttle body relearn or idle relearn procedure after cleaning or replacement
Replace the electronic throttle body if cleaning and wiring checks do not resolve the issue
Reprogram or replace the PCM only after all other causes have been ruled out

Idle signal faults often misdiagnosed

A dirty throttle body is a very common cause of P1510 on GM vehicles, and cleaning it often resolves the code without replacing any parts.
The idle signal circuit is part of the throttle actuator control system, so a problem with the accelerator pedal sensor can set this code even though the throttle body itself is fine.
Aftermarket remote starters or alarm systems tapped into the idle circuit can introduce voltage irregularities that trigger P1510.
A low or failing battery can cause erratic idle signal voltages and set this code; always verify battery condition and charging system output before deeper diagnostics.
Some GM models require a throttle body relearn procedure after cleaning or replacement, and skipping it can cause the code to return immediately.

Can I keep driving with P1510?

You can usually drive the vehicle with P1510 set, but expect possible idle instability or stalling at stops. Avoid aggressive driving and have the fault diagnosed promptly, especially if the engine stalls or enters reduced power mode.

Tools that help

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