DTC Troubleshooting
DTC Troubleshooting: P2646
DTC P2646: Rocker Arm Oil Pressure Switch Circuit Low Voltage
Special Tools Required
- Pressure gauge adapter 07NAJ-P07010A
- A/T low pressure gauge w/panel 07406-0070301
- 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. Reading and Clearing Diagnostic Trouble Codes
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 20.
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.
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 PCM.
NO - Go to step 5.
5. Turn the ignition switch to LOCK (0).
6. Disconnect the rocker arm oil pressure switch 2P connector.
7. Turn the ignition switch to ON (II).
8. Check the VTEC PRES SW in the DATA LIST with the HDS.
Is SWITCH ON indicated?
YES - Go to step 15.
NO - Go to step 9.
9. Turn the ignition switch to LOCK (0).
10. Remove the rocker arm oil pressure switch (A), attach the special tools as shown, then attach the rocker arm oil pressure switch to the pressure gauge adapter (B).
11. Reconnect the rocker arm oil pressure switch 2P connector.
12. Start the engine.
13. Do the VTEC TEST in the INSPECTION MENU with the HDS.
14. Check the oil pressure.
Does the oil pressure increase to at least 392 kPa (4.0 kgf/cm2, 56.9 psi)?
YES - Replace the rocker arm oil pressure switch, Service and Repair then go to step 19.
NO - Inspect the following items. If they are OK, replace the rocker arm oil control solenoid, Service and Repair then go to step 19.
- VTEC system's oil line
- Operation of the rocker arm VTEC Rocker Arm Test
15. Turn the ignition switch to LOCK (0).
16. Jump the SCS line with the HDS.
17. Disconnect PCM connector A (31P).
18. Check for continuity between PCM connector terminal A23 and body ground.
Is there continuity?
YES - Repair short in the wire between the PCM (A23) and the rocker arm oil pressure switch, then go to step 19.
NO - Go to step 26.
19. Reconnect all connectors.
20. Turn the ignition switch to ON (II).
21. Reset the PCM with the HDS.
22. Do the PCM idle learn procedure. PCM Idle Learn Procedure
23. Do the VTEC TEST in the INSPECTION MENU with the HDS.
24. Check for Pending or Confirmed 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 PCM, then go to step 1.
NO - Go to step 25.
25. 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 Pending or Confirmed DTCs were indicated in step 24, 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, the rocker arm oil control valve, and the PCM, then go to step 1. If the screen indicates NOT COMPLETED, go to step 23.
26. Reconnect all connectors.
27. Update the PCM if it does not have the latest software, PCM Update or substitute a known-good PCM. Reading and Clearing Diagnostic Trouble Codes
28. Do the VTEC TEST in the INSPECTION MENU with the HDS.
29. Check for Pending or Confirmed 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 PCM. If the PCM was updated, substitute a known-good PCM, Reading and Clearing Diagnostic Trouble Codes then recheck. If the PCM was substituted, go to step 1.
NO - Go to step 30.
30. Monitor the OBD STATUS for DTC P2646 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM. Service and Repair If any other Pending or Confirmed DTCs were indicated in step 28, 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, the rocker arm oil control solenoid, and the PCM. If the PCM was updated, substitute a known-good PCM, Reading and Clearing Diagnostic Trouble Codes then recheck. If the PCM was substituted, go to step 1. If the screen indicates NOT COMPLETED, keep idling until a result comes on.