DTC Troubleshooting
DTC Troubleshooting: P2646
DTC P2646: Rocker Arm Oil Pressure Switch (VTEC 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 07406-0020201
- A/T pressure hose, 2,210 mm 07MAJ-PY4011A
- A/T pressure adapter 07MAJ-PY40120
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 21.
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 (VTEC oil pressure switch), the rocker arm oil control solenoid (VTEC solenoid valve), and the ECM.
NO - Go to step 5.
5. Turn the ignition switch to LOCK (0).
6. Disconnect the rocker arm oil pressure switch (VTEC 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 (VTEC oil pressure switch) (A) Service and Repair and attach the special tools as shown, then attach the rocker arm oil pressure switch (VTEC oil pressure switch) to the oil pressure gauge adapter (B).
NOTE: Install the parts in the reverse order of removal with a new O-ring.
11. Reconnect the rocker arm oil pressure switch (VTEC oil pressure switch) 2P connector.
12. Start the engine.
13. Do the VTEC TEST in the INSPECTION MENU with the HDS.
14. Check the VETC oil pressure.
Does the oil pressure increase at least 392 kPa (4.0 kgf/cm2, 56.9 psi)?
YES - Replace the rocker arm oil pressure switch (VTEC oil pressure switch), Service and Repair then go to step 20.
NO - Inspect the following items. If they are OK, replace the rocker arm oil control valve (VTEC solenoid valve), Service and Repair then go to step 20.
- VTEC systems 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 ECM connector B (24P).
18. Check for continuity between ECM connector terminal B11 and body ground.
Is there continuity?
YES - Repair short in the wire between the ECM (B11) and the rocker arm oil pressure switch (VTEC 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 ECM with the HDS.
22. Do the ECM idle learn procedure. ECM Idle Learn Procedure
23. Do the VTEC TEST in the INSPECTION MENU with the HDS.
24. 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 (VTEC oil pressure switch), the rocker arm oil control solenoid (VTEC solenoid valve), and the ECM.
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 Temporary DTCs or 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 (VTEC oil pressure switch), the rocker arm oil control solenoid (VTEC solenoid valve), and the ECM, then go to step 1. If the screen indicates NOT COMPLETED, go to step 23.
Inspect the following items. If they are OK, replace the rocker arm oil control valve (VTEC solenoid valve), Service and Repair then go to step 19.
- VTEC system's oil line
- Operation of the rocker arm VTEC Rocker Arm Test
26. Reconnect all connectors.
27. Update the ECM if it does not have the latest software, ECM Update or substitute a known-good ECM. Initial Inspection and Diagnostic Overview
28. Do the VTEC TEST in the INSPECTION MENU with the HDS.
29. 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 (VTEC oil pressure switch), the rocker arm oil control solenoid (VTEC solenoid valve), and the ECM. If the ECM was updated, substitute a known-good ECM, Initial Inspection and Diagnostic Overview then go to step 28. If the ECM 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 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 29, 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 (VTEC oil pressure switch), the rocker arm oil control solenoid (VTEC solenoid valve), and the ECM. If the ECM was updated, substitute a known-good ECM, Initial Inspection and Diagnostic Overview then go to step 28. If the ECM was substituted, go to step 1. If the screen indicates NOT COMPLETED, go to step 28.