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-   -   P2646 dead end, out of ideas, help (https://hondaforum.com/forum/general-tech-help-37/p2646-dead-end-out-ideas-help-17275/)

Mr.Black 04-10-2024 02:23 PM
P2646 dead end, out of ideas, help
 
2006 Honda crv 4cyl auto (US)

I have been fighting with the p2646 code for the better part of a year now and I'm at a complete loss for ideas. I've changed the vtec solenoid twice, the VVT solenoid, the screen up front behind the tensioner pulley, the oil and filter, I've treated the oil to clean gunk out and changed the oil 4 more times while treating it. The screens are all clear, the oil is clean, the filter is new and I still can't go 3 miles without the code coming back and the vehicle going into limp home mode (tries to quit over 3k rpm).

I've got no other ideas and anything I find online says its something I've already fixed.

Any ideas would be helpful. Any electrical problems I could look for?

grcauto 04-10-2024 09:18 PM
Glean what you can from this. You'll likely need to load test the circuits.

Operation CHARM: Car repair manuals for everyone.
Home >> Honda Truck >> 2006 >> CR-V 2WD L4-2.4L >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P2646

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 07406-0070300
- 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-S5A0200

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, 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/PCM.

NO - Go to step 5.

5. Turn the ignition switch OFF.
6. Disconnect the rocker arm oil pressure switch (VTEC 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 ON indicated?

YES - Go to step 14.

NO - Go to step 9.

9. Turn the ignition switch OFF.

https://charm.li/images/IMP03Q313/asian151/48004265/


10. Remove the rocker arm oil pressure switch (VTEC oil pressure switch) (A), install the special tools as shown, then install the rocker arm oil pressure switch (VTEC oil pressure switch) (A) on the oil pressure gauge adapter (B).

NOTE: Install the switch in the reverse order of removal with a new O-ring.

11. Turn the ignition switch ON (II).
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/sq.cm, 56.9 psi)?

YES - Replace the rocker arm oil pressure switch (VTEC oil pressure switch), then go to step 21.

NO - Inspect the VTEC system. If it is OK. Replace the rocker arm oil control solenoid (VTEC solenoid valve), then go to step 19.

14. Turn the ignition switch OFF.
15. Jump the SCS line with the HDS.
16. Disconnect ECM/PCM connector B (24P).

https://charm.li/images/IMP03Q313/asian151/48008920/


17. Check for continuity between ECM/PCM connector terminal B11 and body ground.

Is there continuity?

YES - Repair short in the wire between the ECM/PCM (B11) and the rocker arm oil pressure switch (VTEC oil pressure switch), then go to step 18.

NO - Go to step 25.

18. Reconnect the rocker arm oil pressure switch (VTEC oil pressure switch) 2P connector.
19. Turn the ignition switch ON (II).
20. Reset the ECM/PCM with the HDS.
21. Do the ECM/PCM idle learn procedure.
22. Do the VTEC TEST in the INSPECTION MENU with the HDS.
23. Check for Temporary DTCs or DTCs with the HDS.

Are any Temporary DTCs or DTCs indicated?

YES - If DTC P2646 is indicated, 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/PCM, then go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.

NO - Go to step 24.

24. Monitor the OBD STATUS for DTC P2646 in the DTCs MENU with the HDS.

Does the screen indicate PASSED?

YES - Troubleshooting is complete.

NO - If the screen indicates FAILED, go to step 1 and recheck. If the screen indicates NOT COMPLETED, go to step 22 and recheck.

25. Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM.
26. Do the VTEC TEST in the INSPECTION MENU with the HDS.
27. Check for Temporary DTCs or DTCs with the HDS.

Are any Temporary DTCs or DTCs indicated?

YES - If DTC P2646 is indicated, 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/PCM, then go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.

NO - If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM.
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