Hey fellas,Im getting a few codes back on my 2000PO 231 Fuel Pump Secondary CKT LowPO 475 Ex Pressure Control Valev FaultAny ideas on what these mean and any quick tests to determine what is going on. It is the middle of plowing season after all!! Will most likely get buried once again this week.Any help is appreciated.

 

FK5 KOEO DIAGNOSTIC TROUBLE CODE P0231
Note: Voltage is present for 20 seconds after key on with engine not running.

DTC P0231 indicates voltage was not present on fuel pump monitor circuit when the fuel pump was commanded on.
Possible causes:
open inertia switch
blown F/P fuse
open fuel pump monitor circuit
open fuel pump control circuit
faulty fuel pump relay

KB1 DIAGNOSTIC TROUBLE CODE (DTC) P0475
possible causes:
shorted to power
open/grounded circuit
damaged solenoid
damaged PCM

 

FK5 KOEO DIAGNOSTIC TROUBLE CODE P0231
Note: Voltage is present for 20 seconds after key on with engine not running.

DTC P0231 indicates voltage was not present on fuel pump monitor circuit when the fuel pump was commanded on.
Possible causes:
open inertia switch
blown F/P fuse
open fuel pump monitor circuit
open fuel pump control circuit
faulty fuel pump relay
If DTC P0230 is also present, GO to FK1 .
Disconnect inertia switch harness connector.
Key on, engine off.
Measure voltage of Circuit 238 (DG/Y) between inertia switch harness connector and ground.
Is voltage greater than 10.5 volts?
Yes No
GO to FK6 . GO to FK8 .

FK6 CHECK INERTIA SWITCH
Measure voltage of Circuit 787 (PK/BK) between inertia switch harness connector and ground.
Key off.
Was voltage greater than 10.5 volts?
Yes No
GO to FK7 . RESET or REPLACE inertia switch. RESTORE vehicle. CLEAR DTCs and RETEST.

FK7 CHECK FUEL PUMP MONITOR CIRCUIT
Install breakout box; leave PCM disconnected.
Disconnect inertia switch harness connector.
Measure resistance of Circuit 737 (PK/BK) between inertia switch harness connector and PCM Test Pin 40.
Is resistance less than 5 ohms?
Yes No
REPLACE PCM. RESTORE vehicle. CLEAR DTCs and RETEST. REPAIR open in fuel pump monitor Circuit 737 (PK/BK). RESTORE vehicle. CLEAR DTCs and RETEST.

FK8 CHECK FUEL PUMP FUSE
Key off.
Check fuel pump fuse (for an E-Series Fuse 17, F-Series Fuse 19 or Excursion Fuse 112).
Is fuse OK?
Yes No
GO to FK9 . REPLACE fuse. RESTORE vehicle. CLEAR DTCs and RETEST.

FK9 CHECK FOR POWER TO FUEL PUMP RELAY
Remove fuel pump relay.
Key on, engine off.
For F-Series, measure voltage of Circuit 1059 (LB/O) between Pin 2 of the fuel pump relay harness connector and ground.
For E-Series, measure voltage of Circuit 37 (Y) between Pin 2 of the fuel pump relay harness connector and ground.
Key off.
Was voltage greater than 10.5 volts?
Yes No
GO to FK10 . REPAIR open in Circuit 1059 (LB/O) for F-Series or Circuit 37 (Y) for E-Series. RESTORE vehicle. CLEAR DTCs and RETEST.

FK10 CHECK INERTIA SWITCH FEED CIRCUIT
Disconnect inertia switch harness connector.
Measure resistance of Circuit 238 (DG/Y) between fuel pump relay harness connector Pin 4 and inertia switch harness connector.
Is resistance less than 5 ohms?
Yes No
REPLACE fuel pump relay. RESTORE vehicle. CLEAR DTCs and RETEST. REPAIR open in Circuit 238 (DG/Y). RESTORE vehicle. CLEAR DTCs and RETEST.

 

KB1 DIAGNOSTIC TROUBLE CODE (DTC) P0475
possible causes:
shorted to power
open/grounded circuit
damaged solenoid
damaged PCM
Disconnect EPR harness connector.
Measure resistance between Pin A and ground.
Is the resistance less than 5 ohms?
Yes No
GO to KB2 . REPAIR open in Circuit 570 (BK/WH). RESTORE system. CLEAR DTCs and RETEST.

KB2 CHECK EPR COIL
Measure resistance across EPR coil contacts A and B.
Is the coil resistance between 2.5 ohms and 12 ohms?
Yes No
GO to KB3 . REPLACE regulator. RESTORE system. CLEAR DTCs and RETEST.

KB3 CHECK FOR SHORT TO POWER IN CIRCUIT 318 (GY/RD).
Disconnect PCM harness connector.
Measure voltage between Pin B and ground.
Shake harness.
Is B+ ever present?
Yes No
REPAIR short to power in Circuit 318 (GY/RD). RESTORE system. CLEAR DTCs and RETEST. GO to KB4 .

KB4 CHECK CIRCUIT 318 (GY/RD) FOR SHORT TO GROUND
Measure resistance between Pin B and ground.
Shake harness.
Does the resistance ever drop below 10,000 ohms?
Yes No
REPAIR short to ground in Circuit 318 (GY/RD). RESTORE system. CLEAR DTCs and RETEST. GO to KB5 .

KB5 CHECK FOR OPEN IN CIRCUIT 318 (GY/RD)
Install breakout box; leave PCM disconnected.
Measure resistance between Pin B and Test Pin 42.
Shake harness.
Does resistance ever go above 5 ohms?
Yes No
REPAIR open in Circuit 318 (GY/RD). RESTORE system. CLEAR DTCs and RETEST. GO to KB6 .

KB6 PERFORM OUTPUT STATE CHECK
Key on, engine off.
Measure voltage between EBP connector harness side Pin B and chassis ground.
Run KOEO Output State Self Test on scan tool.
Does voltage toggle between 12 V and 0 V?
Yes No
Fault is intermittent; unable to duplicate failure. RESTORE system. CLEAR DTCs and RETEST. REPLACE PCM. RESTORE system. CLEAR DTCs and RETEST.