Main Relay (Computer/Fuel System): Testing and Inspection
PGM-FI Main Relay Circuit Troubleshooting1. Turn the ignition switch OFF.
2. Disconnect the PGM-FI main relay 7P connector.
3. Check for continuity between body ground and PGM-FI main relay 7P connector terminal No.3.
Is there continuity?
YES - Go to step 4.
NO - Repair open in the wire between the PGM-FI main relay and G1O1.
4. Measure voltage between body ground and PGM-FI main relay 7P connector terminal No.7.
Is there battery voltage?
YES - Go to step 6.
NO - Go to step 5.
5. Check for a blown ACG S (15A) 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 ACG S (15A) fuse.
NO - Repair the open in the wire between the PGM-FI main relay and the ACG S (15A) fuse.
6. Turn the ignition switch ON (II).
7. Measure voltage between body ground and PGM-FI main relay 7P connector terminal No.5.
Is there battery voltage?
YES - Go to step 9.
NO - Go to step 8.
8. Check for a blown No.1 FUEL PUMP (15A) fuse in the driver's under-dash fuse/relay box.
Is the fuse blown?
YES - Repair the short in the wire between the PGM-FI main relay and the No.1 FUEL PUMP (15A) fuse.
NO - Repair the open in the wire between the PGM-FI main relay and the No.1 FUEL PUMP (15A) fuse.
9. Shift to Park, then turn the ignition switch to the START (III) position, and measure voltage between body ground and PGM-FI main relay 7P connector terminal No.2.
Is there battery voltage?
YES - Go to step 11.
NO - Go to step 10.
10. Check for a blown No.13 STARTER SIGNAL (7.5 A) fuse in the driver's under-dash fuse/relay box.
Is the fuse blown?
YES - Repair the short in the wire between the PGM-FI main relay and the No.13 STARTER SIGNAL (7.5A) fuse.
NO - Repair the open in the wire between the PGM-FI main relay and the No.13 STARTER SIGNAL (7.5A).
11. Turn the ignition switch OFF.
12. Disconnect the PCM connector A (32P).
13. Check for continuity between PGM-FI main relay 7P connector terminal No.1 and PCM connector terminal A15.
Is there continuity?
YES - Go to step 14.
NO - Repair open in the wire between the PGM-FI main relay and the PCM (A15).
14. Reconnect the PCM connector A (32P) and the PGM-FI main relay 7P connector.
15. Turn the ignition switch ON (II).
16. Measure voltage between the PCM connector terminals B1 and B2, and between B9 and B2.
Is there battery voltage?
YES - Go to step 17.
NO -Check for an open in the wires between the PGM-FI main relay and the PCM (B1, B9). If the wires are OK, replace the PGM-FI main relay.
17. Turn the ignition switch OFF, then ON (II) again.
18. Measure voltage between PCM 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 - PGM-FI main relay may be faulty; go to step 19.
NO - Substitute a known-good PCM and recheck. If prescribed voltage is now available, replace the original PCM.
19. Remove the PGM-FI main relay.
20. Connect battery power to PGM-FI main relay 7P connector terminal No.2 and connect ground to PGM-FI main relay 7P connector terminal No.1. Then check for continuity between PGM-FI main relay 7P connector terminals No.5 and No.4.
NOTE: Use the terminal number shown. Ignore the terminal numbers molded into the relay.
Is there continuity?
YES - Go to step 21.
NO - Replace the PGM-FI main relay and reset.
21. Connect battery power to PGM-FI main relay 7P connector terminal No.5, and connect ground to PGM-FI main relay 7P connector terminal No.3. Then check for continuity between PGM-FI main relay 7P connector terminals No.7 and No.6.
Is there continuity?
YES - Go to step 22.
NO - Replace the PGM-FI main relay and reset.
22. Connect battery power to PGM-FI main relay 7P connector terminal No.6, and connect ground to PGM-FI main relay 7P connector terminal No.1. Then check for continuity between PGM-FI main relay 7P connector terminals No.5 and No.4.
Is there continuity?
YES - The PGM-FI main relay is OK.
NO - Replace the PGM-FI main relay and retest.