Diagnostic Aids

WARNING: This page is about a different car, the 1995 Lincoln Continental. However, it is still accessible from the selected car via links, so may be relevant.

Perform this test when instructed during QUICK TEST or if directed by other test procedures. This test is used to diagnose the following:

Fuel pump driver module.
Inertia Fuel Shutoff (IFS) switch.
Wiring Harness Circuits (B+, FUEL PUMP, FPM, POWER-TO-PUMP and VPWR).
Constant Control Relay Module (CCRM).
Powertrain Control Module (PCM).

Fig 1: Fuel Pump Driver Module Test Circuit & Connector Terminals

1) DTC P1233 Or P1234

Turn ignition off. Connect scan tester to Data Link Connector. Turn ignition on. Using scan tester, access FPM PID. If FPM PID is 20-80 percent, go to step 25). If FPM PID is not 20-80 percent, go to next step.

2)

If engine will start, go to step 15). If engine will not start, verify IFS switch is set and go to next step.

3)

Turn ignition off. Disconnect FPDM wiring harness connector. Turn ignition on. Measure voltage between connector terminals GND and POWER-TO-FPDM. If voltage is 10.5 volts or more, replace FPDM and repeat QUICK TEST . If voltage is less than 10.5 volts, go to step 7).
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 3) to step 7). No test procedures have been omitted.

7)

Leave ignition on and FPDM disconnected. Measure voltage between chassis ground and connector terminal POWER-TO-FPDM. If voltage is 10.5 volts or more, repair open circuit and repeat QUICK TEST . If voltage is less than 10.5 volts, go to next step.

8)

Turn ignition off. Leave FPDM disconnected. Disconnect CCRM. Measure voltage between chassis ground and terminal No. 11 (B+) of CCRM connector. If voltage is less than 10.5 volts, repair open circuit to CCRM and repeat QUICK TEST . If voltage is 10.5 volts or more, to next step.

9)

Turn ignition off. Leave FPDM and CCRM disconnected. Disconnect scan tester (if applicable). Measure resistance between negative battery terminal and terminal No. 8 (GND) of CCRM connector. If resistance is 5 ohms or more, repair open circuit to CCRM and repeat QUICK TEST . If resistance is less than 5 ohms, go to next step.

10)

Leave ignition off. Leave FPDM and CCRM disconnected. Measure resistance between POWER-TO-FPDM terminal of FPDM connector and terminal No. 5 of CCRM connector. If resistance is 5 ohms or more, go to step 13). If resistance is less than 5 ohms, reconnect FPDM and go to next step.

11)

Leave ignition off. Leave CCRM disconnected. Disconnect EEC-V power relay. Measure resistance between VPWR terminal of EEC-V power relay connector and terminal No. 13 (VPWR) of CCRM connector. If resistance is 5 ohms or less, replace CCRM and repeat QUICK TEST . If resistance is more than 5 ohms, repair open in VPWR circuit between EEC-V power relay and CCRM.

Fig 2: Identifying EEC-V Power Relay Connector Terminals

NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 11) to step 13). No test procedures have been omitted.

13)

Leave ignition off. Leave CCRM and FPDM disconnected. Disconnect IFS switch. Measure resistance between POWER-TO-FPDM terminal of IFS switch connector and terminal No. 5 of CCRM connector. Measure resistance between POWER-TO-FPDM terminal of FPDM connector and POWER-TO-FPDM terminal of IFS switch connector. If resistance is 5 ohms or less, replace IFS switch and repeat QUICK TEST . If resistance is more than 5 ohms, repair open circuit and repeat QUICK TEST .
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 13) to step 15). No test procedures have been omitted.

15)

Turn ignition off. Disconnect FPDM wiring harness connector. Disconnect PCM wiring harness connector. Inspect pins for damage and repair as necessary. Install EEC-V Breakout Box (014-000950), leaving PCM disconnected. Measure resistance between test pin No. 40 (FPM) at breakout box and FPM terminal of FPDM connector. If resistance is 5 ohms or less, go to next step. If resistance is more than 5 ohms, repair open in FPM circuit and repeat QUICK TEST .

16)

Leave FPDM disconnected. Turn ignition on. Measure voltage between test pin No. 40 and 51 (PWR GND) at breakout box. If voltage is one volt or less, go to next step. If voltage is more than one volt, repair FPM circuit short to power and repeat QUICK TEST .

17)

Leave FPDM disconnected. Turn ignition off. Disconnect scan tester from DLC (if applicable). Measure resistance between test pin No. 40 and test pins No. 51, 76 and 91 at breakout box. If each resistance measurement is 10,000 ohms or more, go to next step. If any resistance measurement is less than 10,000 ohms, repair circuit short to ground and repeat QUICK TEST .

18)

Reconnect FPDM. Turn ignition on. Measure voltage between test pins No. 40 and 76 (PWR GND) at breakout box. If voltage is 0.2-1.0 volt, replace PCM and repeat QUICK TEST . If voltage is not 0.2-1.0 volt, replace FPDM and repeat QUICK TEST .
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 18) to step 25). No test procedures have been omitted.

25) Check For Intermittent Short Or Open Circuit

Scan tester should be connected to DLC and in FPM PID. Observe FPM PID for indication of fault while lightly tapping on CCRM, FPDM and IFS switch. Fault will be indicated if FPM PID goes outside 20-80 percent range. Wiggle and bend all FPDM system related wiring harness and connectors. If any faults are found, isolate and repair as necessary. repeat QUICK TEST . If no faults are found, problem cannot be duplicated at this time. Go to CIRCUIT TEST Z .
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 25) to step 30). No test procedures have been omitted.

30) DTC P0230, P1235 Or P1236

Turn ignition off. Connect scan tester to Data Link Connector (DLC). Turn ignition on. Using scan tester, access FPM PID. If FPM PID is not 20-80 percent, go to step 40). If FPM PID is 20-80 percent, go to next step.

31)

Turn ignition off. Disconnect FPDM wiring harness connector. Disconnect PCM wiring harness connector. Inspect pins for damage and repair as necessary. Install EEC-V Breakout Box (014-000950), leaving PCM disconnected. Measure resistance between test pin No. 80 (FP) at breakout box and FP terminal of FPDM connector. If resistance is 5 ohms or less, go to next step. If resistance is more than 5 ohms, repair open in FP circuit and repeat QUICK TEST .

32)

Leave FPDM disconnected. Turn ignition on. Measure voltage between test pin No. 51 (PWR GND) and 80 (FP) at breakout box. If voltage is one volt or less, go to next step. If voltage is more than one volt, repair FP circuit short to power and repeat QUICK TEST .

33)

Leave FPDM disconnected. Turn ignition off. Disconnect scan tester from DLC (if applicable). Measure resistance between test pin No. 80 and test pins No. 51, 76 and 91 at breakout box. If each resistance measurement is 10,000 ohms or more, go to next step. If any resistance measurement is less than 10,000 ohms, repair circuit short to ground and repeat QUICK TEST .

34)

Reconnect FPDM. Turn ignition on. Measure voltage between test pin No. 51 (PWR GND) and 80 at breakout box. If voltage is 4.5-5.5 volts, replace PCM and repeat QUICK TEST . If voltage is not 4.5-5.5 volts, replace FPDM and repeat QUICK TEST .
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 34) to step 40). No test procedures have been omitted.

40) Check For Intermittent Short Or Open Circuit

Scan tester should be connected to DLC and in FPM PID. Observe FPM PID for indication of fault while lightly tapping on CCRM, FPDM and IFS switch. Fault will be indicated if FPM PID goes outside 20-80 percent range. Wiggle and bend all FPDM system related wiring harness and connectors. If any faults are found, isolate and repair as necessary. repeat QUICK TEST . If no faults are found, problem cannot be duplicated at this time. Go to CIRCUIT TEST Z .
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 40) to step 47). No test procedures have been omitted.

47) DTC P1237 Or P1238

Turn ignition off. Connect scan tester to Data Link Connector. Turn ignition on. Using scan tester, access FPM PID. If FPM PID is 70-80 percent, go to next step. If FPM PID is not 70-80 percent, go to step 57).

48)

If engine will start, go to step 62). If engine will not start, go to next step.

49)

Turn ignition off. Disconnect scan tester (if applicable). Disconnect FPDM wiring harness connector. Measure resistance between FPDM connector terminals FUEL PUMP GROUND and POWER-TO-PUMP. If resistance is 10 ohms or more, go to step 54). If resistance is less than 10 ohms, go to next step.

50)

Leave FPDM disconnected. Turn ignition on. Measure voltage between chassis ground and FUEL PUMP GROUND terminal at FPDM connector. If voltage is one volt or more, repair circuit short to power and repeat QUICK TEST . If voltage is less than one volt, go to next step.

51)

Turn ignition off. Disconnect fuel pump wiring harness connector. Measure resistance between negative battery terminal and POWER-TO-PUMP terminal at FPDM connector. If resistance is 10,000 ohms or more, go to next step. If resistance is less than 10,000 ohms, repair circuit short to ground and repeat QUICK TEST .

52) Check For Power To Fuel Pump

Turn ignition off. Leave fuel pump disconnected. Reconnect FPDM. Turn ignition on. Measure voltage between fuel pump terminals at connector. Turn ignition off. If voltage is 10 volts or more, replace fuel pump and repeat QUICK TEST . If voltage is less than 10 volts, verify battery is full charged. If battery is okay, replace FPDM and repeat QUICK TEST .
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 52) to step 54). No test procedures have been omitted.

54) Isolate Open Circuit

Turn ignition off. Disconnect FPDM. Measure resistance of POWER-TO-PUMP circuit between fuel pump and FPDM connector. Measure resistance of FUEL PUMP GROUND circuit between fuel pump and FPDM connector. Measure internal resistance of fuel pump. If each resistance measurement is less than 10 ohms, no faults are present. Verify results of previous steps. If any resistance measurement is 10 ohms or more, repair open circuit or replace fuel pump. repeat QUICK TEST .
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 54) to step 57). No test procedures have been omitted.

57) Check Fuel Pump Secondary Circuit

Leave ignition on. Using scan tester, access Output Test Mode. Command outputs on (to activate fuel pump). Listen for fuel pump to activate. Listen to fuel pump for indication of fault while lightly tapping on fuel pump and FPDM. Fault will be indicated if fuel pump shuts off. Wiggle and bend POWER-TO-PUMP and FUEL PUMP GROUND circuit between fuel pump and FPDM. If any faults are found, isolate and repair as necessary. repeat QUICK TEST . If no faults are found, problem cannot be duplicated at this time. Go to CIRCUIT TEST Z .
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 57) to step 62). No test procedures have been omitted.

62) Check FPDM

Turn ignition off. Disconnect FPDM. Turn ignition on. Listen for fuel pump to activate. If fuel pump activates, repair POWER-TO-PUMP circuit short to power. If fuel pump does not activate, replace FPDM.