LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Honda >> 1990 >> Civic Base, 2D Hatchback >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests - EFI >> Fuel System >> Fuel Control >> Fuel Pump Main Relay Harness
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Fuel Pump Main Relay Harness

  1. Turn ignition off. Disconnect main relay connector. Check for continuity between connector terminal No. 2 and body ground. See Fig 1 and Fig 2 . If continuity exists, go to next step. If continuity does not exist, repair open in Black wire from No. 2 terminal.
    Fig 1: Main Relay Harness Terminals (Accord)
    G90I17150Courtesy of AMERICAN HONDA MOTOR CO., INC.
    Fig 2: Main Relay Harness Terminals (Civic, CRX & Prelude)
    G90J17151Courtesy of AMERICAN HONDA MOTOR CO., INC.
  2. Measure voltage between connector terminals No. 1 (positive) and No. 2 (negative). See Fig 1 and Fig 2 . If battery voltage is present, go to next step. If battery voltage is not present, check wiring between battery and main relay as well as EFI/ECU fuse (ECU fuse on Accord and CRX) in underhood relay box.
  3. Turn ignition switch to ON position. Measure voltage between connector terminals No. 5 (positive) and No. 2 (negative). See Fig 1 and Fig 2 . If battery voltage is present, go to next step. If battery voltage is not present, check wiring from ignition switch and main relay. Check No. 12 fuse (No. 2 on Accord) in dash fuse box and wiring from fuse box to main relay. Repair or replace as necessary.
  4. Connect voltmeter to connector terminals No. 4 (positive) (No. 6 on Accord) and No. 2 (negative). See Fig 1 and Fig 2 . Turn ignition switch to START position. If specified voltage is present, go to next step. If battery voltage (approximately 10 volts on Accord) is not present, check wiring between ignition switch and main relay. Check No. 1 fuse (A/T) or No. 3 fuse (M/T) (No. 9 fuse on Accord) and wiring from fuse box to main relay. Repair or replace as necessary.
  5. Connect a jumper wire between connector terminals No. 5 and No. 7. See Fig 1 and Fig 2 . Turn ignition switch to ON position. Fuel pump should operate. If fuel pump does not operate, check wiring to and from fuel pump.