DTC P1233: Fuel Pump Driver Module Disabled Or Off Line

P1233 - FUEL PUMP DRIVER MODULE DISABLED OR OFF LINE

Description:	LS: This DTC indicates the powertrain control module (PCM) is not receiving the fuel pump information on the communication link from the rear electronics module (REM). Refer to the appropriate MULTIFUNCTION ELECTRONIC MODULES article for REM selftest/diagnostics. All Others: The powertrain control module (PCM) monitors the fuel pump monitor (FPM) circuit from the fuel pump driver module (FPDM). With the key ON, engine OFF or key ON, engine running the FPDM continuously sends a duty cycle signal to the PCM through the FPM circuit. The test fails if the PCM stops receiving the duty cycle signal.
Possible Causes:	Inertia fuel shutoff (IFS) switch needs to be reset Open FPDM ground circuit Open circuit to FPDM PWR RLY Open FPDM PWR circuit Open or shorted FPM circuit (engine should start) Damaged IFS switch Damaged FPDM PWR RLY Damaged FPDM
Diagnostic Aids:	The PCM expects to see one of the following duty cycle signals from the FPDM on the FPM circuit: 1) 50% (500 ms on, 500 ms off), all OK. 2) 25% (250 ms on, 750 ms off), FPDM did not receive a fuel pump (FP) duty cycle command from the PCM, or the duty cycle that was received was invalid. 3) 75% (750 ms on, 250 off), the FPDM has detected a concern in the circuits between the FPDM and the fuel pump.
Application	Key On Engine Off	Key On Engine Running	Continuous Memory
LS	Refer to the MULTIFUNCTION ELECTRONIC MODULES for rear electronics module (REM) diagnostics.
All others	GO to Pinpoint Test KB .