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PGM-FI Main Relay Test




NOTE: PGM-FI Main Relay Sticks in ON Position
On 1998-2002 Accords with A/T, if the PGM-FI main relay sticks in the ON position after you trun the ignition switch to LOCK (0), the PCM can repeatedly set these A/T DTCs:
- P0753 (shift solenoid valve A)
- P0758 (shift solenoid valve B)
- P1705 (transmission range switch short to ground)
- P1768 (A/T clutch pressure control solenoid valve A)


To check for a sticking PGM-FI main relay, here's what you do:.

1. Connect the PGM Tester to the 16P data link connector.
2. Turn the ignition switch to LOCK (0), and watch the PGM Tester display screen. You should see the message NO COMMUNICATION as soon as you turn the key to LOCK (0).
- If you see the NO COMMUNICATION message, the main relay is OK. Continue with normal troubleshooting.
- If you don't see the NO COMMUNICATION message, and there's continued communication with the PCM, the main relay is defective and must be replaced.


PGM-FI Main Relay Circuit - Normal Troubleshooting

1. Turn the ignition switch OFF, then disconnect the PGM-FI main relay 7P connector.




2. Check for continuity between body ground and PGM-FI main relay 7P connector terminal No.3.

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 7P connector terminal No.7.

Is there battery voltage?

YES - Go to step 5.

NO - Go to step 4.

4. Check for a blown ACG S (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 ACG S (15 A) fuse.

NO - Repair the open in the wire between the PGM-FI main relay and the ACG S (15 A) fuse.




5. Turn the ignition switch ON (II), and measure voltage between body ground and PGM-FI main relay 7P connector terminal No.5.

Is there battery voltage?

YES - Go to step 7.

NO - Go to step 6.

6. Check for a blown No.1 FUEL PUMP (15 A) fuse in the [1][2]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 (15 A) fuse.

NO - Repair the open in the wire between the PGM-FI main relay and the No.1 FUEL PUMP (15 A) fuse.




7. Push the clutch pedal in, or 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 9.

NO - Go to step 8

8. Check for a blown No.13 STARTER SIGNAL (7.5 A) fuse in the [1][2]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 (7.5 A) fuse.

NO - Repair the open in the wire between the PGM-FI main relay and the No. 13 STARTER SIGNAL (7.5 A).

9. Turn the ignition switch OFF, and disconnect ECM/PCM connector A (32P).




10. Check for continuity between PGM-FI main relay 7P connector terminal No.1 and ECM/PCM connector terminal A15.

Is there continuity?

YES - Go to step 11.

NO - Repair open in the wire between the PGM-FI main relay and the ECM/PCM (A15).

11. Reconnect ECM/PCM connector A (32P) and the PGM-FI main relay 7P connector.




12. Turn the ignition switch ON (II), and measure voltage between ECM/PCM connector terminals B1 and B20, and between B9 and B20.

Is there battery voltage?

YES - Go to step 13.

NO - Check for an open in the wires between the PGM-FI main relay and the ECM/PCM (B1, B9). If the wires are OK, replace the PGM-FI main relay.




13. Turn the ignition switch OFF, then ON (II) again, and measure voltage between the ECM/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 - The PGM-FI main relay may be faulty. Go to step 14.

NO - Substitute a known-good ECM/PCM and recheck. If the prescribed voltage is now available, replace the original ECM/PCM.

14. Remove the PGM-FI main relay.




15. Connect battery power to the PGM-FI main relay 7P connector terminal No.2, and connect ground to the PGM-FI main relay 7P connector terminal No.1. Then check for continuity between the PGM-FI main relay 7P connector terminals No.5 and No.4.

NOTE: Use the terminal numbers shown. Ignore the terminal numbers molded into the relay.

Is there continuity?

YES - Go to step 16.

NO - Replace the PGM-FI main relay and retest.

16. Connect battery power to the PGM-FI main relay 7P connector terminal No.5, and connect ground to the PGM-FI main relay 7P connector terminal No.3. Then check for continuity between the PGM-FI main relay 7P connector terminals No.7 and No.6.

Is there continuity?

YES - Go to step 17.

NO - Replace the PGM-FI main relay and retest.

17. Connect battery power to the PGM-FI main relay 7P connector terminal No.6, and connect ground to the PGM-FI main relay 7P connector terminal No.1. Then check for continuity between the 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 reply and retest.


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