Fault code P1642 – a step-by-step guide to diagnosing and fixing it

Error code P1642 is displayed and the check engine light is on - what does this mean?

The DTC P1642 is a manufacturer-specific fault code that is recognized by the OBD system and indicates a problem with the fuel pump driver or fuel pump control. This trouble code mainly occurs in Chrysler, Dodge and Jeep vehicles and indicates a fault in the fuel supply system.

What can cause this error code?

• Defective fuel pump
• Damaged fuel pump relay
• Defective fuel pump driver in the PCM
• Interrupted or damaged wiring to the fuel pump
• Corroded or loose plug connections
• Defective fuel pump fuse
• Low fuel pressure due to clogged filter
• Faulty ground wire of the fuel pump

What symptoms occur in parallel with fault code P1642?

• Starting problems: The vehicle is difficult or impossible to start
• Jerky engine: Irregular engine running, especially at low engine speeds
• Loss of power: Reduced engine power while driving
• Engine stuttering: Interruptions when accelerating or under load
• Engine stalling: Engine stalls while driving
• Smell of fuel: smell of gasoline in or around the vehicle

How can the problem with error code P1642 be rectified?

• The repair requires a systematic diagnosis of the fuel supply. Here are the most important solutions:
• Replace fuel pump relay and check function with a multimeter
• Replace the fuel pump completely if the pressure is below the set values
• Check wiring between PCM and fuel pump for continuity and insulation faults and repair
• Clean all plug connections in the fuel system and treat with contact spray
• Check fuel pump fuse and replace if necessary
• Have PCM fuel pump driver diagnosed and repaired by a specialist company
• Replace fuel filter and measure fuel pressure with pressure gauge