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 underhood 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 (A15).
9. Reconnect ECM connector A (32P) and the PGM-FI main relay connectors.
10. Turn the ignition switch ON (II), 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 two 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.