DTC Troubleshooting
DTC P2646: Rocker Arm Oil Pressure Switch Circuit Low VoltageSpecial Tools Required
- Pressure gauge adapter 07NAJ-P07010A
- A/T low pressure gauge w/panel 07406-0070301
- A/T pressure hose 07406-0020201
- A/T pressure hose, 2,210 mm 07MAJ-PY4011A
- A/T pressure adapter 07MAJ-PY40120
- Oil pressure hose 07ZAJ-S5AA200
NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
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, 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. Turn the ignition switch OFF.
6. Disconnect the rocker arm 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 SWITCH ON indicated?
YES - Go to step 16.
NO - Go to step 9.
9. Turn the ignition switch OFF.
10. Remove the cowl cover and under-cowl panel.
11. Remove the rocker arm oil pressure switch (A), and install the special tools as shown, then install the rocker arm oil pressure switch in the oil pressure gauge attachment (B).
NOTE: Install the parts in the reverse order of removal with a new O-ring.
12. Reconnect the rocker arm oil pressure switch 2P connector.
13. Start the engine.
14. Do the VTEC TEST in the INSPECTION MENU with the HDS.
15. Check the oil pressure.
Does the oil pressure increase to at least 392 kPa (4.0 kgf/sq.cm, 56.9 psi)?
YES - Replace the rocker arm oil pressure switch, then go to step 20.
NO - Inspect the following items. If they are OK, replace the rocker arm oil control valve, then go to step 20.
- VTEC system's oil line
- Operation of the rocker arm
16. Turn the ignition switch OFF.
17. Jump the SCS line with the HDS.
18. Disconnect ECM connector C (44P).
19. Check for continuity between ECM connector terminal C22 and body ground.
Is there continuity?
YES - Repair short in the wire between the ECM (C22) and the rocker arm oil pressure switch, then go to step 20.
NO - Go to step 27.
20. Reconnect all connectors.
21. Turn the ignition switch ON (II).
22. Reset the ECM with the HDS.
23. Do the ECM 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.
Is DTC P2646 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, then go step 1.
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. If any other Temporary DTCs or DTCs were indicated in step 25, go to the indicated DTCs troubleshooting.
NO - If the screen indicates FAILED, check for poor connections or loose terminals at the rocker arm oil pressure switch, the rocker arm oil control solenoid, and the ECM, then go to step 1. If the screen indicates NOT COMPLETED, go to step 24.
27. Reconnect all connectors.
28. Update the ECM if it does not have the latest software, or substitute a known-good ECM.
29. Do the VTEC TEST in the INSPECTION MENU with the HDS.
30. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P2646 indicated?
YES - Check for poor connections or loose terminals at the rocker arm oil pressure switch, the rocker arm oil control valve, and the ECM. If the ECM was updated, substitute a known-good ECM, then go to step 29. If the ECM was substituted, go to step 1.
NO - Go to step 31.
31. Monitor the OBD STATUS for DTC P2646 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. If any other Temporary DTCs or DTCs were indicated in step 30, go to the indicated DTCs troubleshooting.
NO - If the screen indicates FAILED, check for poor connections or loose terminals at the rocker arm oil pressure switch, the rocker arm oil control valve, and the ECM. If the ECM was updated, substitute a known-good ECM, then go to step 29. If the ECM was substituted, go to step 1. If the screen indicates NOT COMPLETED, go to step 29.