DTC P1220: Fuel Pump Control Module (FPCM): Procedure

1. Turn ignition off. Disconnect FPCM harness connector. See Fig 1. Turn ignition on. Measure voltage between body ground and FPCM harness connector terminal No. 4 (Black/Yellow wire). If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit and retest system. See WIRING DIAGRAMS article.
2. Turn ignition off. Disconnect dropping resistor harness connector. See Fig 1. Check continuity between FPCM harness connector terminal No. 1 (Black wire), dropping resistor harness connector Black wire and body ground. Also check circuits for short to voltage. Repair as necessary and retest system. If ground circuits are okay, go to next step.
3. Disconnect fuel level sensor and fuel pump harness connector located behind access cover under rear seat. Check continuity of Green/Red wire between FPCM harness connector terminal No. 2, fuel level sensor and fuel pump harness connector terminal No. 3 and dropping resistor harness connector. See Figure. Also check circuit for short to ground and short to voltage. Repair as necessary and retest system. If circuit is okay, go to next step.
4. Disconnect ECM harness connector. See Figure. Check continuity of Blue/White wire between FPCM harness connector terminal No. 3 and ECM harness connector terminal No. 33. See Figure. Also check circuit for short to ground and short to voltage. Repair as necessary and retest system. If circuit is okay, go to next step.
5. Check continuity of Green/Red wire between fuel level sensor and fuel pump harness connector terminal No. 3 and ECM harness connector terminal No. 94. Also check circuit for short to ground and short to voltage. Repair as necessary and retest system. If circuit is okay, go to next step.
6. Measure resistance between dropping resistor terminals. If resistance is about .8 ohm at 77°F (25°C), go to next step. If resistance is not about .8 ohm at 77°F (25°C), replace dropping resistor and retest system.
7. Reconnect all harness connectors. Start engine and warm to normal operating temperature. Turn ignition off and wait at least 10 seconds. Measure voltage between body ground and FPCM terminal No. 2 (Green/Red wire) by backprobing. While observing voltage, start engine. With engine cranking, voltage should be about .4 volt. After engine starts, voltage should be about 5 volts. If voltage is as specified, go to next step. If voltage is not as specified, replace FPCM and retest system.
8. No problem is indicated at this time. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.

Fig 1: Locating FPCM & Dropping Resistor

Courtesy of NISSAN MOTOR CO., U.S.A.