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P0122

Throttle Position Sensor A Circuit Low Input

The engine computer is receiving a lower-than-normal signal from the throttle position sensor or pedal position sensor. This can cause poor throttle response, rough running, and warning lights. The problem is often a bad sensor, wiring issue, or connector problem.

Severity3/5 Moderate
Can I drive?⚠ With caution

You may be able to drive short distances, but acceleration may be poor or unpredictable. If the engine enters limp mode, stalls, or reacts badly to throttle input, stop driving and repair it promptly.

DIY
$20–$150
Shop
$150–$500
Difficulty
intermediate

What It Means

P0122 means the ECM/PCM detected a low voltage signal on throttle position sensor circuit A, or on some vehicles the accelerator pedal position sensor circuit. The signal is below the expected range, so the computer cannot accurately determine throttle demand. This can trigger reduced power mode, unstable idle, or other drivability problems.

Symptoms

Common Causes

1. Faulty throttle position sensor or accelerator pedal position sensorhigh
2. Damaged wiring, loose connector, or poor terminal contact in the sensor circuithigh
3. Throttle body contamination or throttle plate binding affecting sensor readingsmedium
4. Blown fuse, damaged power supply, or poor sensor reference voltagemedium
5. PCM/ECM issue or software problemlow

Related Codes

FAQ

Is P0122 caused by the throttle body or the pedal sensor?

It can be either, depending on the vehicle. Some cars use a throttle position sensor on the throttle body, while others rely on the accelerator pedal position sensor and related throttle control sensors.

Can a dirty throttle body cause P0122?

Yes, if carbon buildup makes the throttle plate stick or prevents normal movement. It is more common to see this code from a sensor or wiring fault, but contamination can contribute.

Will P0122 clear itself?

Sometimes the light may go off temporarily if the fault is intermittent, but the problem usually returns until the underlying issue is fixed.

Do I need to replace the throttle body for P0122?

Not always. The sensor, connector, wiring, or power and ground circuits should be checked first before replacing the throttle body.