Variable Valve Timing and Lift Electronic Control (vtec) Acura MDX II

Scheme 243

DTC P2646: Rocker Arm Oil Pressure Switch Circuit Low Voltage

Special Tools Required

1. Pressure gauge adapter 07NAJ-P07010A
2. A/T low pressure gauge w/panel 07406-0070301
3. A/T pressure hose 07406-0020201
4. A/T pressure hose, 2,210 mm 07MAJ-PY4011A
5. A/T pressure adapter 07MAJ-PY40120
6. Oil pressure hose 07ZAJ-S5AA200

Note. Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).

Scheme 244

Scheme 245

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 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 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 15 . NO - Go to step 9.
9. Turn the ignition switch OFF.
10. Remove the rocker arm oil pressure switch (A), install the special tools as shown, then install the rocker arm oil pressure switch on 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 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/cm+ 2 , 56.9 psi)? YES - Replace the rocker arm oil pressure switch (see «ROCKER ARM OIL PRESSURE SWITCH REMOVAL/INSTALLATION»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#variable-valve-timing-and-lift-electronic-control-vtec) ), then go to step 19 . NO - Inspect the following items. If they are OK, replace the rocker arm oil control solenoid (see «ROCKER ARM OIL CONTROL SOLENOID REPLACEMENT»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#variable-valve-timing-and-lift-electronic-control-vtec) ), then go to step 19 . VTEC system's oil line Operation of the rocker arm (see «VTEC ROCKER ARM TEST»(/acura/mdx/ii-2006-2010/remont/mechanical/#cylinder-head__vtec-rocker-arm-test) )
15. Turn the ignition switch to LOCK (0).
16. Jump the SCS line with the HDS.
17. Disconnect PCM connector B (49P).
18. Check for continuity between PCM connector terminal B20 and body ground. Is there continuity? YES - Repair short in the wire between the PCM (B20) 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 ON (II).
21. Reset the PCM with the HDS.
22. Do the PCM idle learn procedure (see «PCM IDLE LEARN PROCEDURE»(/acura/mdx/ii-2006-2010/remont/engine-control-systems/#idle-control-system__pcm-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, 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 Temporary DTCs or DTCs were indicated in step 24 , go to the indicated «DTCs troubleshooting»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#variable-valve-timing-and-lift-electronic-control-vtec) . 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 (see «PCM UPDATE»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#pgm-fi-system__pcm-update) ), or substitute a known-good PCM (see «SUBSTITUTING THE PCM»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#fuel-and-emissions-systems__substituting-the-pcm) ).
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, the rocker arm oil control solenoid, and the PCM. If the PCM was updated, substitute a known-good PCM (see «SUBSTITUTING THE PCM»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#fuel-and-emissions-systems__substituting-the-pcm) ), 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 (see «PCM REPLACEMENT»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#pgm-fi-system__pcm-replacement) ). If any other Temporary DTCs or DTCs were indicated in step 28 , 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 PCM. If the PCM was updated, substitute a known-good PCM (see «SUBSTITUTING THE PCM»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#fuel-and-emissions-systems__substituting-the-pcm) ), then recheck. If the PCM was substituted, go to step 1 . If the screen indicates NOT COMPLETED, keep idling until a result comes on.

DTC P2647: Rocker Arm Oil Pressure Switch Circuit High Voltage

Note. Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).

Scheme 246

Scheme 247

Scheme 248

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 16 .
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 PCM. NO - Go to step 5.
5. Check the result of step 4 . VTEC Switch Failure VTEC Switch Open VTEC Switch SIG Line Open VTEC Switch GND Line Open Is the test result any of the above? YES - Go to step 6. NO - Check for poor connections or loose terminals at the rocker arm oil pressure switch. If it is OK, replace the rocker arm oil control solenoid assembly (see «ROCKER ARM OIL CONTROL SOLENOID REPLACEMENT»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#variable-valve-timing-and-lift-electronic-control-vtec) ), then go to step 15 .
6. Turn the ignition switch to LOCK (0).
7. Disconnect the rocker arm oil pressure switch 2P connector.
8. At the rocker arm oil pressure switch side, check for continuity between rocker arm oil pressure switch 2P connector terminals No. 1 and No. 2. Is there continuity? YES - Go to step 9. NO - Replace the rocker arm oil pressure switch (see «ROCKER ARM OIL PRESSURE SWITCH REMOVAL/INSTALLATION»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#variable-valve-timing-and-lift-electronic-control-vtec) ), then go to step 16 .
9. Turn the ignition switch ON (II).
10. Measure voltage between rocker arm oil pressure switch 2P connector terminal No. 1 and body ground. Is there battery voltage? YES - Repair open in the wire between the rocker arm oil pressure switch and G101, then go to step 15 . NO - Go to step 11.
11. Turn the ignition switch OFF.
12. Jump the SCS line with the HDS.
13. Disconnect PCM connector B (49P).
14. Check for continuity between PCM connector terminal B20 and rocker arm oil pressure switch 2P connector terminal No. 1. Is there continuity? YES - Go to step 22 . NO - Repair open in the wire between the PCM (B20) and the rocker arm oil pressure switch, then go to step 16 .
15. Turn the ignition switch to LOCK (0).
16. Reconnect all connectors.
17. Turn the ignition switch ON (II).
18. Reset the PCM with the HDS.
19. Do the PCM idle learn procedure (see «PCM IDLE LEARN PROCEDURE»(/acura/mdx/ii-2006-2010/remont/engine-control-systems/#idle-control-system__pcm-idle-learn-procedure) ).
20. Check for Temporary DTCs or DTCs with the HDS. Is DTC P2647 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 - Go to step 21.
21. Monitor the OBD STATUS for DTC P2647 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 20 , 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 PCM, then go to step 1 . If the screen indicates NOT COMPLETED, keep idling until a result comes on.
22. Reconnect all connectors.
23. Update the PCM if it does not have the latest software (see «PCM UPDATE»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#pgm-fi-system__pcm-update) ), or substitute a known-good PCM (see «SUBSTITUTING THE PCM»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#fuel-and-emissions-systems__substituting-the-pcm) ).
24. Start the engine.
25. Check for Temporary DTCs or DTCs with the HDS. Is DTC P2647 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 (see «SUBSTITUTING THE PCM»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#fuel-and-emissions-systems__substituting-the-pcm) ), then recheck. If the PCM was substituted, go to step 1 . NO - Go to step 26.
26. Monitor the OBD STATUS for DTC P2647 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 (see «PCM REPLACEMENT»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#pgm-fi-system__pcm-replacement) ). 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 PCM. If the PCM was updated, substitute a known-good PCM (see «SUBSTITUTING THE PCM»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#fuel-and-emissions-systems__substituting-the-pcm) ), then recheck. If the PCM was substituted, go to step 1 . If the screen indicates NOT COMPLETED, keep idling until a result comes on.

DTC P2648: Rocker Arm Oil Control Solenoid Circuit Low Voltage

Note. Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).

Scheme 249

Scheme 250

1. Turn the ignition switch ON (II).
2. Clear the DTC with the HDS.
3. 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 control solenoid and the PCM. NO - Go to step 4.
4. Turn the ignition switch to LOCK (0).
5. Disconnect the rocker arm oil control solenoid 1P connector.
6. At the solenoid side, measure resistance between the rocker arm oil control solenoid 1P connector terminal and the solenoid valve body. Is there 14-30 ohms at room temperature? YES - Go to step 7. NO - Go to step 10 .
7. Jump the SCS line with the HDS.
8. Disconnect PCM connector B (49P).
9. Check for continuity between PCM connector terminal B39 and body ground. Is there continuity? YES - Repair short in the wire between the PCM (B39) and the rocker arm oil control solenoid, then go to step 11 . NO - Go to step 18 .
10. Replace the rocker arm oil control solenoid (see «ROCKER ARM OIL CONTROL SOLENOID REPLACEMENT»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#variable-valve-timing-and-lift-electronic-control-vtec) ).
11. Reconnect all connectors.
12. Turn the ignition switch ON (II).
13. Reset the PCM with the HDS.
14. Do the PCM idle learn procedure (see «PCM IDLE LEARN PROCEDURE»(/acura/mdx/ii-2006-2010/remont/engine-control-systems/#idle-control-system__pcm-idle-learn-procedure) ).
15. Do the VTEC TEST in the INSPECTION MENU with the HDS.
16. Check for Temporary DTCs or DTCs with the HDS. Is DTC P2648 indicated? YES - Check for poor connections or loose terminals at the rocker arm oil control solenoid and the PCM, then go to step 1 . NO - Go to step 17.
17. Monitor the OBD STATUS for DTC P2648 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 16 , go to the indicated DTCs troubleshooting. NO - If the screen indicates FAILED, check for poor connections or loose terminals at the rocker arm oil control solenoid and the PCM, then go to step 1 . If the screen indicates NOT COMPLETED, go to step 15 .
18. Reconnect all connectors.
19. Update the PCM if it does not have the latest software (see «PCM UPDATE»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#pgm-fi-system__pcm-update) ), or substitute a known-good PCM (see «SUBSTITUTING THE PCM»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#fuel-and-emissions-systems__substituting-the-pcm) ).
20. Do the VTEC TEST in the INSPECTION MENU with the HDS.
21. Check for Temporary DTCs or DTCs with the HDS. Is DTC P2648 indicated? YES - Check for poor connections or loose terminals at the rocker arm oil control solenoid and the PCM. If the PCM was updated, substitute a known-good PCM (see «SUBSTITUTING THE PCM»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#fuel-and-emissions-systems__substituting-the-pcm) ), then recheck. If the PCM was substituted, go to step 1 . NO - Go to step 22.
22. Monitor the OBD STATUS for DTC P2648 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 (see «PCM REPLACEMENT»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#pgm-fi-system__pcm-replacement) ). If any other Temporary DTCs or DTCs were indicated in step 21 , go to the indicated «DTCs troubleshooting»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#variable-valve-timing-and-lift-electronic-control-vtec) . NO - If the screen indicates FAILED, check for poor connections or loose terminals at the rocker arm oil control solenoid and the PCM. If the PCM was updated, substitute a known-good PCM (see «SUBSTITUTING THE PCM»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#fuel-and-emissions-systems__substituting-the-pcm) ), then recheck. If the PCM was substituted, go to step 1 . If the screen indicates NOT COMPLETED, go to step 20 .

DTC P2649: Rocker Arm Oil Control Solenoid Circuit High Voltage

Note. Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).

Scheme 251

Scheme 252

1. Turn the ignition switch ON (II).
2. Clear the DTC with the HDS.
3. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, then let it idle.
4. Check for Temporary DTCs or DTCs with the HDS. Is DTC P2649 indicated? YES - Go to step 5. NO - Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the rocker arm oil control solenoid and the PCM.
5. Turn the ignition switch OFF.
6. Disconnect the rocker arm oil control solenoid 1P connector.
7. At the solenoid side, measure resistance between the rocker arm oil control solenoid 1P connector terminal and the solenoid valve body. Is there 14-30 ohms at room temperature? YES - Go to step 8. NO - Go to step 11 .
8. Jump the SCS line with the HDS.
9. Disconnect PCM connector B (49P).
10. Check for continuity between PCM connector terminal B39 and the rocker arm oil control solenoid 1P connector terminal. Is there continuity? YES - Go to step 18 . NO - Repair open in the wire between the PCM (B39) and the rocker arm oil control solenoid, then go to step 12 .
11. Replace the rocker arm oil control solenoid (see «ROCKER ARM OIL CONTROL SOLENOID REPLACEMENT»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#variable-valve-timing-and-lift-electronic-control-vtec) ).
12. Reconnect ail connectors.
13. Turn the ignition switch ON (II).
14. Reset the PCM with the HDS.
15. Do the PCM idle learn procedure (see «PCM IDLE LEARN PROCEDURE»(/acura/mdx/ii-2006-2010/remont/engine-control-systems/#idle-control-system__pcm-idle-learn-procedure) ).
16. Check for Temporary DTCs or DTCs with the HDS. Is DTC P2649 indicated? YES - Check for poor connections or loose terminals at the rocker arm oil control solenoid and the PCM, then go to step 1 . NO - Go to step 17.
17. Monitor the OBD STATUS for DTC P2649 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 16 , go to the indicated DTCs troubleshooting. NO - If the screen indicates FAILED, check for poor connections or loose terminals at the rocker arm oil control solenoid and the PCM, then go to step 1 . If the screen indicates NOT COMPLETED, keep idling until a result comes on.
18. Reconnect all connectors.
19. Update the PCM if it does not have the latest software (see «PCM UPDATE»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#pgm-fi-system__pcm-update) ), or substitute a known-good PCM (see «SUBSTITUTING THE PCM»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#fuel-and-emissions-systems__substituting-the-pcm) ).
20. Start the engine, and let it idle.
21. Check for Temporary DTCs or DTCs with the HDS. Is DTC P2649 indicated? YES - Check for poor connections or loose terminals at the rocker arm oil control solenoid and the PCM. If the PCM was updated, substitute a known-good PCM (see «SUBSTITUTING THE PCM»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#fuel-and-emissions-systems__substituting-the-pcm) ), then recheck. If the PCM was substituted, go to step 1 . NO - Go to step 22.
22. Monitor the OBD STATUS for DTC P2649 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 (see «PCM REPLACEMENT»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#pgm-fi-system__pcm-replacement) ). If any other Temporary DTCs or DTCs were indicated in step 21 , go to the indicated DTCs troubleshooting. NO - If the screen indicates FAILED, check for poor connections or loose terminals at the rocker arm oil control solenoid and the PCM. If the PCM was updated, substitute a known-good PCM (see «SUBSTITUTING THE PCM»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#fuel-and-emissions-systems__substituting-the-pcm) ), then recheck. If the PCM was substituted, go to step 1 . If the screen indicates NOT COMPLETED, go to step 20 .

Scheme 253

Scheme 254

1. Remove the rocker arm oil control solenoid/oil filter assembly (A) from the oil pump, and check the rocker arm oil control solenoid filter (B) for a restriction. If there is a restriction, replace the rocker arm oil control solenoid filter, the engine oil filter, and the engine oil.
2. If the filter is not restricted, remove the rocker arm oil control solenoid (A), and push the valve (B) with your finger to check its movement. If the valve moves freely, it is normal; check the engine oil pressure (see «OIL PRESSURE TEST»(/acura/mdx/ii-2006-2010/remont/lubrication-system/#engine-lubrication__oil-pressure-test) ). If the engine oil is OK, replace the rocker arm oil control solenoid (see «ROCKER ARM OIL CONTROL SOLENOID REPLACEMENT»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#variable-valve-timing-and-lift-electronic-control-vtec) ). If the valve binds or sticks, replace the rocker arm oil control solenoid assembly.

Scheme 255

1. Disconnect the rocker arm oil control solenoid connector (A).
2. Remove the rocker arm oil control solenoid (B).
3. Install the parts in the reverse order of removal with a new O-ring (C).

Scheme 256

1. Disconnect the rocker arm oil pressure switch connector (A), then remove the rocker arm oil pressure switch (B).
2. Install the parts in the reverse order of removal with a new O-ring (C).

See also:
• GENERAL TROUBLESHOOTING INFORMATION
• VTEC ROCKER ARM TEST
• PCM IDLE LEARN PROCEDURE
• PCM UPDATE
• SUBSTITUTING THE PCM
• PCM REPLACEMENT
• OIL PRESSURE TEST
• ROCKER ARM OIL PRESSURE SWITCH REMOVAL/INSTALLATION