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 Test Hose 07AAJ-PY4A100
- 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 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 19.
2. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.
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), or press the engine start/stop button to select the OFF mode.
6. Disconnect the rocker arm oil pressure switch 2P connector.
7. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.
8. Check the VTEC PRES SW in the DATA LIST with the HDS.
Is switch ON indicated?
YES -
Go to step 14.
NO -
Go to step 9.
9. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.
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 oil pressure gauge adapter (B).
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 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 18.
NO -
Inspect the VTEC system. If it is OK, replace the rocker arm oil control solenoid Service and Repair, then go to step 18.
14. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.
15. Jump the SCS line with the HDS.
16. Disconnect PCM connector B (49P).
17. Check for continuity between PCM connector terminal B20 and body ground.
Is there continuity?
YES -
Repair a short in the wire between the PCM(B20) and the rocker arm oil pressure switch, then go to step 18.
NO -
Go to step 24.
18. Reconnect all connectors.
19. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.
20. Reset the PCM with the HDS.
21. Do the PCM idle learn procedure PCM Idle Learn Procedure.
22. Do the VTEC TEST in the INSPECTION MENU with the HDS.
23. 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, then go to step 1.
NO -
Troubleshooting is complete. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.�
24. Reconnect all connectors.
25. Update the PCM if it does not have the latest software PCM Update, or substitute a known-good PCM.
26. Do the VTEC TEST in the INSPECTION MENU with the HDS.
27. 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, then go to step 26. If the PCM was substituted, go to step 1.
NO -
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 are indicated, go to the indicated DTC's troubleshooting.�