P0121 on Chevrolet
Throttle/Pedal Position Sensor Circuit Range/Performance
P0121 on Chevrolet vehicles indicates throttle/pedal position sensor circuit range/performance. Au7o has documented this code across 1 Chevrolet model — most commonly on Impala. This code means the throttle position (or accelerator pedal position) sensor's signal does not match what the computer expects compared with other inputs like airflow, RPM, and the second throttle/pedal sensor. The sensor tells the computer how far the throttle or pedal is open; when its range or performance is off, the computer can't trust how much power you're requesting. You may notice hesitation, surging, poor acceleration, rough idle, or the vehicle dropping into a reduced-power 'limp' mode. It indicates an out-of-range or implausible signal rather than a complete loss of signal. Typical repair costs on Chevrolet range from $100 to $450, depending on the specific model and root cause.
Common Causes of P0121
- •Worn or failing throttle position sensor
- •Dirty or carboned-up throttle body affecting plate position
- •Damaged, frayed, or shorted sensor wiring
- •Corroded or loose sensor connector
- •Poor sensor ground or reference voltage
- •Faulty throttle body / electronic throttle actuator
- •Mismatch between the two throttle or pedal sensor signals
P0121 on Chevrolet by Model
Chevrolet Impala(1 issue)
- Reduced Engine Power / Service StabiliTrak from Throttle Body Failure2006-2016
Impalas frequently throw a cluster of warnings at once — 'Engine Power Reduced,' 'Service StabiliTrak,' and 'Service Traction Control' — that are usually one underlying drive-by-wire fault rather than three separate failures. The most common root cause is the electronic throttle body actuator (or the dual throttle-position sensors inside it) going out of range; the accelerator pedal position sensors can also disagree. Because the ECM cross-checks these dual sensors, any disagreement forces the car into limp-home mode with drastically reduced power. Carbon buildup on the throttle plate aggravates it, especially in cold weather.
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View P0121 across all makes →Frequently Asked Questions
What does P0121 mean on Chevrolet?▼
P0121 stands for "Throttle/Pedal Position Sensor Circuit Range/Performance." This code means the throttle position (or accelerator pedal position) sensor's signal does not match what the computer expects compared with other inputs like airflow, RPM, and the second throttle/pedal sensor. The sensor tells the computer how far the throttle or pedal is open; when its range or performance is off, the computer can't trust how much power you're requesting. You may notice hesitation, surging, poor acceleration, rough idle, or the vehicle dropping into a reduced-power 'limp' mode. It indicates an out-of-range or implausible signal rather than a complete loss of signal. On Chevrolet specifically, this code is documented across 1 model.
What causes P0121 on Chevrolet vehicles?▼
Common causes on Chevrolet: Worn or failing throttle position sensor, Dirty or carboned-up throttle body affecting plate position, Damaged, frayed, or shorted sensor wiring, Corroded or loose sensor connector, Poor sensor ground or reference voltage. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0121 on a Chevrolet?▼
Repair costs on Chevrolet range from $100 to $450, depending on the specific model and root cause.
Which Chevrolet models have P0121 documented?▼
Au7o has documented P0121 on 1 Chevrolet model: Impala.