1996 Isuzu Oasis LSFACTORY OEM SERVICE PROCEDURE

Main Relay Harness Check

  1. Turn ignition off. Unplug PGM-FI main relay harness connector. Check for continuity between ground and relay harness connector terminal No. 3. See Fig 1 . If continuity exists, go to next step. If continuity does not exist, repair open in Black wire between ground and relay harness connector terminal No. 3. See WIRING DIAGRAMS  section.
  2. Measure voltage between ground and relay harness connector terminal No. 1. If battery voltage exists, go to next step. If battery voltage does not exist, check wiring between battery and main relay, also check PCM fuse in underhood relay box. Repair as necessary. See WIRING DIAGRAMS  section.
  3. Turn ignition on. Measure voltage between ground and relay harness connector terminal No. 5. 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. 2. Check wiring from fuse box to main relay. Repair or replace as necessary. See WIRING DIAGRAMS section.
  4. Connect voltmeter to ground and relay harness connector terminal No. 2. Turn ignition switch to START position. If battery voltage exists, go to next step. If battery voltage does not exist, check wiring between ignition switch and main relay. Check wiring from fuse box to main relay. Repair or replace STARTER SIGNAL fuse or wiring as necessary. See WIRING DIAGRAMS  section.
  5. Turn ignition off. Disconnect PCM harness connector "A". See Figure . Check for continuity between relay harness connector terminal No. 1 and PCM harness connector terminal A16. If continuity exists, go to next step. If continuity does not exist, repair open in wire between relay harness connector terminal No. 1 and PCM harness connector terminal A16. See WIRING DIAGRAMS  section.
  6. Reconnect PCM and relay harness connectors. Turn ignition on. Measure voltage between PCM connector terminals A10 and A11 and between A10 and A24. If battery voltage exists, go to next step. If battery voltage does not exist, repair open in wire between PCM connector terminal A11 or A24 and relay harness connector. See WIRING DIAGRAMS section. If wire(s) is okay, replace main relay.
  7. Turn ignition off. Measure voltage between PCM harness connector terminals A10 and A16 for 2 seconds when the ignition switch is first turned on. If one volt or less exists, check PGM-FI main relay. See PGM-FI MAIN RELAY TEST under RELAYS & SOLENOIDS. If one volt or less does not exist, substitute a known-good PCM and recheck. If one volt or less now exists, replace original PCM.
Fig 1: PGM-FI Main Relay Harness Connector Terminal ID (Oasis)
G96I09617Courtesy of AMERICAN HONDA MOTOR CO., INC.
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