DTC P1231 Fuel Pump Relay High Voltage

Diagnostic Trouble Code (DTC) P1231

Fuel Pump Relay High Voltage




Circuit Details


  • In this circuit the ECM mobilizes the fuel pump relay and run the in-tank fuel pump no sooner the ignition is turned ON.
  • As long as the ECM receives reference pulses from the ignition the fuel pump will continue to operate.





Time for setting the DTC

Task boosted after DTC sets

When will DTC clear?

1) This DTC can be stored in "key-on" status

1) The Malfunction Indicator Lamp (MIL) will be seen glowing.


1) The MIL will go off after repetitive ignition cycles in which the diagnostic runs perfectly

2) An open or high voltage condition exists.


2) The ECM will begin to record operating conditions at the time when the diagnostic fails which will be stored in the Freeze Frame.


2) A history DTC will clear by itself after 40 successive warm-up cycles flawlessly


3) The Coolant fan is seen to turn ON.



3) The scan tool can be used to remove all existing DTCs.



4) A history DTC will be stored.


4) Disconnecting the ECM battery feed for 10 seconds



Diagnostic Tools


You might find an intermittent problem may be caused by a) poor connection b) rubbed through wire insulation, or c) wire that is broken inside the insulation.


If you apprehend that any circuitry is erroneous then check up the following conditions:

  • Broken locks
  • Physical damage to the wiring harness
  • Backed out terminals
  • Improper mating
  • Damaged terminals
  • Poor terminals to wire connection