P0120high severityPowertrain
Throttle/Pedal Position Sensor/Switch A Circuit
on 1997 Mazda 626 2.0L I4 · FWD
What this code means
General malfunction in the throttle position sensor (TPS) or accelerator pedal position sensor circuit.
Symptoms
- Check Engine Light
- Erratic idle
- Poor throttle response
- Limp mode
- Stalling
Common causes
- Faulty TPS
- Wiring damage
- Throttle body issue
- PCM failure
Diagnostic steps
- Test TPS voltage sweep (smooth transition 0.5-4.5V)
- Inspect wiring
- Check throttle body
- Test reference voltage
Repair notes
Replace TPS or throttle body assembly. Some vehicles require TPS relearn procedure.
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