P2646

DTC P2646: VTEC Oil Pressure Switch Circuit Low Voltage

Special Tools Required
- Pressure gauge adapter 07NAJ-P07010A
- A/T low pressure gauge w/panel 07406-0070300
- A/T pressure hose 07406-0020201
- A/T pressure hose, 2,210 mm 07MAJ-PY4011A
- A/T pressure adapter 07MAJ-PY40120
- 0il pressure hose 07ZAJ-S5A0200

1. Check the engine oil level.

Is the level OK?

YES - Go to step 2.

NO - Adjust the engine oil to the proper level, then go to step 21.

2. Turn the ignition switch ON (II).
3. Clear the DTC with the HDS.
4. Do the VTEC TEST in the INSPECTION MENU with the HDS.

Is the result OK?

YES - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the VTEC oil pressure switch, the VTEC solenoid valve and the ECM/PCM.

NO - Go to step 5.

5. Turn the ignition switch OFF.
6. Disconnect the VTEC oil pressure switch 2P connector.
7. Turn the ignition switch ON (II).
8. Check the VTEC PRES SW in the DATA LIST with the HDS.

Is ON indicated?

YES - Go to step 14.

NO - Go to step 9.

9. Turn the ignition switch OFF.




10. Remove the VTEC oil pressure switch (A) and install the special tools as shown, then install the VTEC oil pressure switch (A) to the oil pressure gauge adapter (B).

NOTE: Install the switch in the reverse order of removal with a new O-ring.

11. Start the engine.
12. Do the VTEC TEST in the INSPECTION MENU with the HDS.
13. Check the oil pressure.

Does the oil pressure increase to 392 kpa (4.0 kgf/sq.cm, 56.9 psi)?

YES - Replace the VTEC oil pressure switch, then go to step 21.

NO - Inspect the VTEC system. If it is OK. Replace the VTEC solenoid valve, then go to step 21.

14. Turn the ignition switch OFF.
15. Jump the SCS line with the HDS
16. Disconnect the VTEC oil pressure switch 2P connector.
17. Disconnect ECM/PCM connector E (31P).




18. Check for continuity between ECM/PCM connector terminal E23 and body ground.

Is there continuity?

YES - Repair short in the wire between the ECM/PCM (E23) and the VTEC oil pressure switch, then go to step 19.

NO - Go to step 27.

19. Reconnect the VTEC oil pressure switch 2P connector.
20. Reconnect ECM/PCM connector E (31P).
21. Turn the ignition switch ON (II).
22. Reset the ECM/PCM with the HDS.
23. Do the ECM/PCM idle learn procedure.
24. Do the VTEC TEST in the INSPECTION MENU with the HDS.
25. Check for Temporary DTCs or DTCs with the HDS.

Are any Temporary DTCs or DTCs indicated?

YES - If DTC P2646 is indicated, check for poor connections or loose terminals at the VTEC oil pressure switch, the VTEC solenoid valve, and the ECM/PCM, then go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.

NO - Go to step 26.

26. Monitor the OBD STATUS for DTC P2646 in the DTCs MENU with the HDS.

Does the screen indicate PASSED?

YES - Troubleshooting is complete.

NO - If the screen indicates FAILED, go to step 1 and recheck. If the screen indicates NOT COMPLETED, go to step 24 and recheck.

27. Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM.
28. Do the VTEC TEST in the INSPECTION MENU with the HDS.
29. Check for Temporary DTCs or DTCs with the HDS.

Are any Temporary DTCs or DTCs indicated?

YES - If DTC P2646 is indicated, check for poor connections or loose terminals at the VTEC oil pressure switch, the VTEC solenoid valve, and the ECM/PCM then go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.

NO - If the ECM/PCM was updated, troubleshooting is completed. If the ECM/PCM was substituted, replace the original ECM/PCM.