PGM-FI Main Relay Circuit Troubleshooting
PGM-FI Main Relay Circuit Troubleshooting1. Turn the ignition switch OFF.
2. Disconnect the PGM-FI main relay (IGP) 4P connector.
3. Check for continuity between body ground and PGM-FI main relay (IGP) 4P connector terminal No.3.
Is there continuity?
YES - Repair short in the wire between ECM connector terminal A8 and the PGM-FI main relay (IGP).
NO - Go to step 4.
4. Measure voltage between body ground and PGM-FI main relay (IGP) 4P connector terminals No.2 and No.4 individually.
Is there battery voltage?
YES - Go to step 6.
NO - Go to step 5.
5. Check for a blown No.7 (15 A) fuse in the under-hood fuse/relay box.
Is the fuse blown?
YES - Repair short in the wire between the PGM-FI main relay (IGP) and the No.7 (15 A)fuse.
NO - Repair open in the wire between the PGM-FI main relay (IGP) and the No.7 (15 A) fuse.
6 Turn the ignition switch ON (II).
7. Measure voltage between PGM-FI main relay (FUEL PUMP) 4P connector terminal No.2 and body ground.
Is there battery voltage?
YES - Go to step 9.
NO - Go to step 8.
8. Check for a blown No.2 (15 A) fuse in the under-dash fuse/relay box.
Is the fuse blown?
YES - Repair short in the wire between the PGM-FI main relay (FUEL PUMP) and the No.2 (15 A) fuse.
NO - Repair open in the wire between the PGM-FI main relay (FUEL PUMP) and the No.2 (15 A) fuse.
9. Turn the ignition switch OFF.
10. Disconnect ECM connector A (32P).
11. 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 12.
NO - Repair open in the wire between the PGM-FI main relay (FUEL PUMP) and the ECM (A15).
12. Reconnect ECM connector A (32P) and the PGM-FI main relay (FUEL PUMP) connectors.
13. Turn the ignition switch ON (II).
14. Measure voltage between body ground and ECM connector terminals B1 and B9 individually.
Is there battery voltage?
YES - Go to step 15.
NO - Check for an open in the wires between the PGM-FI main relay (IGP) and the ECM (B1, B9). If the wires are OK, replace the PGM-FI main relay.
15. Turn the ignition switch OFF.
16. Turn the ignition switch ON (II), and measure voltage between ECM connector terminals A15 and B2 within 2 seconds.
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.