Fuel Pump Main Relay Harness
- Turn ignition off. Disconnect main relay harness connector. Check for continuity between connector terminal No. 2 and chassis ground. See Fig 1. If continuity exists, go to next step. If continuity does not exist, repair open in Black wire from No. 2 terminal. See WIRING DIAGRAMS
article in the ENGINE PERFORMANCE Section.
- Using a voltmeter, measure voltage between connector terminals No. 1 (positive) and body ground. See Fig 1. If battery voltage exists, go to next step. If battery voltage does not exist, check wiring between battery and main relay as well as ECU fuse in underhood relay box. Repair as required.
- Turn on ignition. Measure voltage between connector terminal No. 5 (positive) and body ground. See Fig 1. If battery voltage exists, go to next step. If battery voltage does not exist, check wiring from ignition switch and main relay. Check fuse No. 23 on Prelude, No. 2 on Accord or AGC on Civic (in dash fuse box). Check wiring from fuse box to main relay. Repair or replace as necessary.
- Connect voltmeter to connector terminals No. 6 (positive) and body ground. See Fig 1. Turn ignition switch to START position. If battery voltage is present, go to next step. If specified voltage is not present, check wiring between ignition switch and main relay. Check fuse No. 9. Check wiring from fuse box to main relay. Repair or replace as necessary.
- Connect a jumper wire between connector terminals No. 5 and No. 7. See Fig 1. Turn on ignition. Fuel pump should operate. If fuel pump fails to operate, check fuel pump wiring.
Courtesy of AMERICAN HONDA MOTOR CO., INC.