P0121 – Throttle/Pedal Position Sensor A Range/Performance
Description
The ECM detects an incorrect or inconsistent signal from the throttle position sensor compared to expected values.
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Compare Diagnostic ScannersSymptoms
- Hesitation
- Poor acceleration
- Rough idle
- Surging
- Check engine light
Causes
- Faulty TPS sensor
- Wiring issues
- Dirty throttle body
- ECM fault
- Connector corrosion
Diagnosis
- Monitor TPS voltage
- Inspect wiring
- Clean throttle body
- Compare TPS values to spec
Repair
- Replace TPS sensor
- Repair wiring
- Clean throttle body
- Replace ECM if needed
