P0231Powertrain
Powertrain · SAE
Fuel Pump Secondary Circuit Low
Meaning
Voltage in the fuel pump secondary feedback circuit is below the minimum expected threshold. The ECM uses this circuit to confirm the pump is actually running; a low signal indicates the pump is not spinning or the feedback path is broken.
Common causes
- Failed fuel pump (motor shorted or open)
- Short to ground in the secondary circuit wiring
- Pump relay not closing correctly
- Disconnected or corroded pump connector
- Pump circuit fuse blown
Symptoms
- Check-engine light on
- No-start
- Pump does not hum with key in on position
- No pressure in the fuel circuit
- Sudden engine stall while driving
Severity
High: the pump is not operating; the vehicle cannot be started or will stop; repair immediately.
What to do
- Check voltage at the pump connector with the relay energised
- Measure fuel pump resistance (compare against specification)
- Check the pump circuit fuse and relay
- Inspect secondary circuit wiring for shorts to ground
- Replace the fuel pump if failed