P1234 – Fuel Pump Speed Signal Fault
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Symptoms
- Loss of power
- Hesitation
- Surging
- Hard starting
- Check engine light
Causes
- Faulty pump speed sensor
- Wiring issue
- Control module fault
- Pump module failure
- Connector corrosion
Diagnosis
- Check speed feedback signal
- Inspect wiring
- Check connectors
- Scope signal at module
- Scan live data
Repair
- Replace pump module
- Repair wiring
- Clean connectors
- Replace control module if needed
- Clear codes and retest