P0121 on Cadillac
Throttle/Pedal Position Sensor Circuit Range/Performance
P0121 on Cadillac vehicles indicates throttle/pedal position sensor circuit range/performance. Au7o has documented this code across 1 Cadillac model — most commonly on Escalade. 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 Cadillac range from $150 to $1,800, 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 Cadillac by Model
Cadillac Escalade(1 issue)
- Service StabiliTrak With Reduced Engine Power on GMT900 Escalade2007-2014
GMT900 Escalades commonly throw 'Service StabiliTrak' and 'Service Traction Control' together with a reduced-engine-power event, and owners chase it for months because three unrelated root causes present identically. The most common is the electronic throttle body - carbon buildup on the blade and a worn throttle position sensor track make the two APP/TPS signals disagree, the PCM defaults to limp mode, and StabiliTrak disables itself because it can no longer command torque reduction. The second is the brake pressure sensor or the EBCM internally, which sets a chassis code and disables ESC without any engine symptom. The third is a weak battery or corroded ground causing a low-voltage brownout that trips every chassis module at once. CarComplaints lists 'Stabiltrak Light On' as the #3 problem on the 2007 Escalade at an average of $1,800 and 75,000 miles, and the 2007 model year carries 41 NHTSA engine complaints alongside a large ESC-related brakes group on 2011.
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What does P0121 mean on Cadillac?▼
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 Cadillac specifically, this code is documented across 1 model.
What causes P0121 on Cadillac vehicles?▼
Common causes on Cadillac: 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 Cadillac?▼
Repair costs on Cadillac range from $150 to $1,800, depending on the specific model and root cause.
Which Cadillac models have P0121 documented?▼
Au7o has documented P0121 on 1 Cadillac model: Escalade.