DTC Troubleshooting

DTC Troubleshooting: P2647

DTC P2647: Rocker Arm Oil Pressure Switch Circuit High Voltage

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information. Initial Inspection and Diagnostic Overview

1. Check the engine oil level.

Is the engine oil level OK?
YES - Go to step 2.

NO - Adjust the engine oil to the proper level, then go to step 17.


2. Turn the ignition switch to ON (II).

3. Clear the DTC with the HDS.

4. Do the VTEC TEST in the INSPECTION MENU with the HDS.
NOTE: If the DTC is stored during VTEC TEST, check for DTC's MENU. If DTC P2647 indicated, go to step 6. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.

Is the result OK?
YES - Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the rocker arm oil pressure switch, the rocker arm oil control solenoid, and the ECM.

NO - Go to step 5.


5. Check the result of step 4.
- VTEC Switch Failure

- VTEC Switch Open

- VTEC Switch SIG Line Open

- VTEC Switch GND Line Open

Is the test result any of the above?
YES - Go to step 6.

NO - Check for poor connections or loose terminals at the rocker arm oil pressure switch. If it is OK, replace the rocker arm oil control solenoid, Rocker Arm Oil Control Solenoid Replacement (M/T) then go to step 15.


6. Turn the ignition switch to LOCK (0).

7. Disconnect the rocker arm oil pressure switch 2P connector.

8. At the rocker arm oil pressure switch side, check for continuity between rocker arm oil pressure switch 2P connector terminals No. 1 and No. 2.

Is there continuity?
YES - Go to step 9.

NO - Replace the rocker arm oil pressure switch, Rocker Arm Oil Pressure Switch Removal/Installation (M/T) then go to step 16.






9. Turn the ignition switch to ON (II).

10. Measure the voltage between rocker arm oil pressure switch 2P connector terminal No. 1 and body ground.

Is there battery voltage?
YES - Repair open in the wire between the rocker arm oil pressure switch and G101, then go to step 15.

NO - Go to step 11.






11. Turn the ignition switch to LOCK (0).

12. Jump the SCS line with the HDS.

13. Disconnect ECM connector B (49P).

14. Check for continuity between ECM connector terminal B20 and rocker arm oil pressure switch 2P connector terminal No. 1.

Is there continuity?
YES - Go to step 22.

NO - Repair open in the wire between the ECM (B20) and the rocker arm oil pressure switch, then go to step 16.






15. Turn the ignition switch to LOCK (0).

16. Reconnect all connectors.

17. Turn the ignition switch to ON (II).

18. Reset the ECM with the HDS.

19. Do the ECM idle learn procedure. ECM/PCM Idle Learn Procedure

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

Is DTC P2647 indicated?
YES - Check for poor connections or loose terminals at the rocker arm oil pressure switch and the ECM, then go to step 1.

NO - Go to step 21.


21. Monitor the OBD STATUS for DTC P2647 in the DTCs MENU with the HDS.

Does the screen indicate PASSED?
YES - Troubleshooting is complete. If any other Temporary DTCs or DTCs were indicated in step 20, go to the indicated DTC's troubleshooting.

NO - If the screen indicates FAILED, check for poor connections or loose terminals at the rocker arm oil pressure switch and the ECM, then go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.


22. Reconnect all connectors.

23. Update the ECM if it does not have the latest software, ECM/PCM Update or substitute a known-good ECM. Initial Inspection and Diagnostic Overview

24. Start the engine, and let it idle.

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

Is DTC P2647 indicated?
YES - Check for poor connections or loose terminals at the rocker arm oil pressure switch, the rocker arm oil control solenoid, and the ECM. If the ECM was updated, substitute a known-good ECM, Initial Inspection and Diagnostic Overview then go to step 24. If the ECM was substituted, go to step 1.

NO - Go to step 26.


26. Monitor the OBD STATUS for DTC P2647 in the DTCs MENU with the HDS.

Does the screen indicate PASSED?
YES - If the ECM was updated, troubleshooting is complete. If the ECM was substituted, replace the original ECM. Service and Repair If any other Temporary DTCs or DTCs were indicated in step 25, go to the indicated DTC's troubleshooting.

NO - If the screen indicates FAILED, check for poor connections or loose terminals at the rocker arm oil pressure switch and the ECM. If the ECM was updated, substitute a known-good ECM, Initial Inspection and Diagnostic Overview then go to step 24. If the ECM was substituted, go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.