DTC Troubleshooting: P1535 (176-1)

DTC P1535:  PGM-FI Main Relay Circuit Malfunction

1.Turn the ignition switch ON (II).

2.Clear the DTC with the HDS.

3.Check for Temporary DTCs or DTCs with the HDS.

Is DTC P1535 indicated?


YES - Go to 4.


NO - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at PGM-FI main relay 1 and the ECM.n


4.Turn the ignition switch OFF.

5.Substitute a known-good PGM-FI main relay 1.

6.Turn the ignition switch ON (II).

7.Clear the DTC with the HDS.

8.Check for Temporary DTCs or DTCs with the HDS.

Is DTC P1535 indicated?


YES - Go to 11.


NO - Replace original PGM-FI main relay 1, then go to 9.


9.Reset the ECM with the HDS.

10.Check for Temporary DTCs or DTCs with the HDS.

Are any Temporary DTCs or DTCs indicated?


YES - If DTC P1535 is indicated, check for poor connections or loose terminals at PGM-FI main relay 1 and the ECM, then go to 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.


NO - Troubleshooting is complete.n

11.Update the ECM if it does not have the latest software, or substitute a known-good ECM.

12.Check for Temporary DTCs or DTCs with the HDS.

Are any Temporary DTCs or DTCs indicated?


YES - If DTC P1535 is indicated, check for poor connections or loose terminals at PGM-FI main relay 1 and the ECM, then go to 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.


NO - If the ECM was updated, troubleshooting is complete. If the ECM was substituted, replace the original ECM.n