P0628

Symptoms

• The Check Engine light comes on
• Unstable engine starting
• Intermittent failures during acceleration
• The engine stalls periodically
• Unstable fuel pressure during diagnosis

Causes

• Oxidation or poor contact in the pump relay connector
• Partial wire break in the control circuit
• Discharged battery - voltage drop when starting
• High resistance in the ECU ground circuit
• Weak output transistor for pump control in the ECU

How to Fix

1. Check and charge the battery
2. Clean fuel pump relay contacts
3. Check the resistance of the pump control circuit wire
4. Measure the voltage drop at each section of the circuit
5. Check ECU grounding
6. If external circuits are in good working order - ECU diagnostics

Related codes

Error P0628 by Vehicle Brand