P0120high severityPowertrain
Throttle/Pedal Position Sensor/Switch A Circuit
on 1998 BMW 528i 2.8L I6 M52 · RWD
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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Other Powertrain codes on this vehicle
29CC
Misfire Cylinder 1
29CD
Misfire Cylinder 2
29CE
Misfire Cylinder 3
29CF
Misfire Cylinder 4
29D0
Misfire Cylinder 5
29D1
Misfire Cylinder 6
29D2
Misfire Cylinder 7
29E0
Lambda Additive/Idle Adaptation Limit, Bank 1
29E1
Lambda Additive/Idle Adaptation Limit, Bank 2
29E2
Lambda Multiplicative Part-Load Adaptation Limit, Bank 1