PGM-FI Main Relay Circuit Troubleshooting
PGM-FI Main Relay Circuit Troubleshooting1. Turn the ignition switch OFF, then disconnect the PGM-FI main relay connectors.
2. Check for continuity between body ground and PGM-FI main relay diode 2P connector terminal No. 2.
Is there continuity?
YES - Go to step 3.
NO - Repair open in the wire between the PGM-FI main relay and G101.
3. Measure voltage between body ground and PGM-FI main relay (IGP) 4P connector terminal No. 2.
Is there battery voltage?
YES - Go to step 5.
NO - Go to step 4.
4. Check for a blown No. 7 (15 A) fuse in the under-hood fuse/relay box.
Is the fuse blown?
YES - Repair the short in the wire between the PGM-FI main relay and the No. 7 (15 A) fuse.
NO - Repair the open in the wire between the PGM-FI main relay and the No. 7 (15 A) fuse.
5. Turn the ignition switch ON (II). Measure voltage between body ground and PGM-FI main relay (fuel pump) 4P connector terminal No. 2, and between PGM-FI main relay (IGP) 4P connector terminal No. 4.
Is there battery voltage?
YES - Go to step 7.
NO - Go to step 6.
6. Check for a blown No. 2 (15 A) fuse in the under-dash fuse/relay box.
Is the fuse blown?
YES - Repair the short in the wire between PGM-FI main relay and the No. 2 fuse.
NO - Repair the open in the wire between the PGM-FI main relay and the No. 2 (15 A) fuse.
7. Turn the ignition switch OFF, and disconnect ECM connector A (32P).
8. Check for continuity between PGM-FI main relay (fuel pump) 4P connector terminal No. 3 and ECM connector terminal A15.
Is there continuity?
YES - Go to step 9.
NO - Repair open in the wire between the PGM-FI main relay and the ECM (A151.
9. Reconnect ECM connector A (32P) and the PGM-FI main relay connectors.
10. Turn the ignition switch ON (11), and measure voltage between ECM connector terminals B1 and B20, and between B9 and B20.
Is there battery voltage?
YES - Go to step 11.
NO - Check for an open in the wires between the PGM-FI main relay and the ECM (B1, B9). If the wires are OK, replace the PGM-FI main relay.
11. Turn the ignition switch OFF, then ON (II) again, and measure voltage between ECM connector terminals A15 and B2 within the first 2 seconds after the ignition switch is turned ON (II).
Is there 1.0 V or less?
YES - The PGM-FI main relay may be faulty.
NO - Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.