P0120high severityPowertrain
Throttle/Pedal Position Sensor/Switch A Circuit
on 2003 Subaru Legacy 3.0L H6 · AWD
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.
Other Powertrain codes on this vehicle
P0001
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P0002
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P0003
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P0004
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P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0011
Intake Camshaft Position Timing Over-Advanced Bank 1
P0012
Intake Camshaft Position Timing Over-Retarded Bank 1
P0013
Exhaust Camshaft Position Actuator Circuit/Open Bank 1
P0014
Exhaust Camshaft Position Timing Over-Advanced Bank 1
P0015
Exhaust Camshaft Position Timing Over-Retarded Bank 1