DTC P1220: Fuel Pump Control Module (FPCM)
- Check Power Supply - Turn ignition off. Disconnect FPCM harness connector. See Fig 2. Using a voltmeter, measure voltage between FPCM connector terminal No. 3 (Yellow/Black wire) and ground. If battery voltage exists, go to next step. If battery voltage does not exist, check for fault in Yellow/Black wire.
- Check Ground Circuit - Turn ignition off. Disconnect dropping resistor harness connector. Check continuity between dropping resistor connector terminal No. 2 (Black wire) and ground. Also, check continuity between FPCM harness connector terminal No. 2 (Black wire) and ground. If continuity exists, go to next step. If no continuity exists, repair fault in Black wire and retest system.
- Disconnect fuel pump harness connector from fuel tank. Check continuity as follows:
- Between dropping resistor harness connector terminal No. 1 (Blue wire) and fuel pump harness connector terminal No. 3 (Blue wire). Continuity should be present.
- Between dropping resistor harness connector terminal No. 1 and FPCM connector terminal No. 1 (Blue wire). Continuity should be present.
- Between ground and fuel pump harness connector terminal No. 3 (Blue wire). Continuity should not be present.
- Between ground and FPCM connector terminal No. 1 (Blue wire). Continuity should not be present.
If continuity is as specified, go to next step. If continuity is not as specified, repair fault in Blue wire.
- Check Output Signal Circuit - Turn ignition off. Disconnect ECM harness connector. Using an ohmmeter, check continuity between ECM harness connector terminal No. 15 and FPCM harness connector terminal No. 4 (Orange/Blue wire). If no continuity exists, repair open in Orange/Blue wire. If continuity exists, go to next step.
- Check Input Signal Circuit
- Using an ohmmeter, check continuity as follows:
- Between ECM harness connector terminal No. 62 and FPCM harness connector terminal No. 1 (Blue wire). Continuity should be present.
- Between ECM harness connector terminal No. 62 and fuel pump harness connector terminal No. 3 (Blue wire). Continuity should be present.
- Between ECM harness connector terminal No. 62 (Blue wire) and ground. Continuity should not be present.
If continuity is as specified, go to next step. If continuity is not as specified, repair fault in Blue wire.
- Check Dropping Resistor - Disconnect dropping resistor harness connector. Measure resistance between connector terminals. See Fig 1. If resistance is about 0.9 ohms at 77°F (25°C), go to next step. If resistance is not about 0.9 ohms at 77°F (25°C), replace dropping resistor.
- Check FPCM - Start engine and warm to operating temperature. Turn ignition off and wait at least 5 seconds. Start engine and allow to idle. Measure voltage between FPCM connector terminals No. 1 and 2. See Fig 2. Voltage should zero volts within 30 seconds of starting engine and about 3.7 volts after 30 seconds of starting engine. If voltage is not as specified, replace FPCM. If voltage is as specified, disconnect and reconnect harness connectors in circuit. Check ECM pin terminals for damage or corrosion. Repair if necessary and retest.