P0627 indicates the engine computer (PCM) has detected an open circuit in the fuel pump control circuit. This means when the PCM attempts to command the fuel pump on, it does not see the expected voltage or ground path, preventing the fuel pump from operating and causing a no-start condition.
The fuel pump relay may be stuck in the open position or have internally failed, preventing power from reaching the fuel pump circuit.
Wiring between the PCM, relay, and fuel pump may be broken, chafed, or corroded at connectors, creating an open circuit.
A shared or dedicated fuse for the fuel pump circuit may have blown due to overload or short.
The fuel pump motor windings may have failed internally, creating an open circuit that the PCM detects.
A bad ground at the fuel pump or relay circuit can prevent proper operation and set this code.
The internal transistor or circuit within the PCM that controls the fuel pump may have failed - this is rare and typically the last cause to investigate.
No. While a failed fuel pump motor can cause this code, it is just one of several possible causes. The fuel pump relay, wiring issues, and blown fuses are more common causes than pump failure itself.
The PCM should be the last item suspected, not the first. Many shops and parts retailers incorrectly recommend PCM replacement for this code, but PCM failure is rare. Always thoroughly diagnose the relay, wiring, fuses, and pump before considering PCM replacement.
The vehicle will likely not start or run because the fuel pump will not operate. This is not a code to ignore; the vehicle will be stranded if the fuel pump does not activate.
Some generic code readers and inexperienced technicians may blame the PCM because the code relates to a 'control circuit,' but proper diagnosis should rule out all external causes (relay, wiring, fuses, pump, grounds) before suspecting the computer.