Common Symptoms
- Check engine light illuminated
- Engine cranks but fails to start
- Engine stalls randomly during operation
- Hesitation or stumbling during acceleration
- Poor fuel pressure or fuel delivery issues
- Fuel pump runs continuously or not at all
Most Likely Root Causes
- Faulty fuel pump control module or relay
- Shorted wiring or connectors in fuel pump control circuit
- Damaged fuel pump control circuit in PCM
- Corroded or loose ground connections
- Failed fuel pump driver circuit in powertrain control module
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Component Location
The fuel pump control module or relay is typically located in the engine compartment fuse box or near the fuel tank.
Manufacturer Notes
Some vehicles use a dedicated fuel pump control module separate from the main PCM that may require independent diagnosis.
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Heavy-duty trucks often throw both OBD-II and J1939 faults simultaneously. AI Diesel Tech handles both protocols in a single guided session.
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