Acura TSX / Honda Accord CL. Manual - part 637

Is there continuity? 

YES: Repair short in the wire between the ECM/PCM (B11) and the VTEC oil pressure 
switch, then go to step 19.  

NO: Go to step 27 .  

Fig. 14: Checking For Continuity Between ECM/PCM Connector Terminal B11 & Body 
Ground 

19. Reconnect the VTEC oil pressure switch 2P connector.  

20. Reconnect ECM/PCM connector B (24P).

 

2004 Acura TSX 

2004 ENGINE PERFORMANCE VTEC/VTC - TSX

  

 

21. Turn the ignition switch ON (II).  

22. Reset the ECM/PCM with the HDS.  

23. Do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE ).  

24. Do the VTEC TEST in the INSPECTION MENU with the HDS.  

25. Check for Temporary DTCs or DTCs in the DTCs MENU 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 VTEC 
oil pressure switch, the 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 troubleshooting.  

NO: Go to step 26.  

26. 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 24 and recheck.  

27. Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM (see 

ECM/PCM UPDATING AND SUBSTITUTION FOR TESTING ).  

28. Do the VTEC TEST in the INSPECTION MENU with the HDS.  

29. Check for Temporary DTCs or DTCs in the DTCs MENU 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 VTEC 
oil pressure switch, the 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 troubleshooting.  

NO: If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was 
substituted, replace the original ECM/PCM (see HOW TO REMOVE THE ECM/PCM 
FOR TESTING ).  

DTC P2647: VTEC OIL PRESSURE SWITCH CIRCUIT HIGH VOLTAGE 

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 14 .  

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 VTEC oil pressure switch and the ECM/PCM.  

NO: Go to step 5.  

 

2004 Acura TSX 

2004 ENGINE PERFORMANCE VTEC/VTC - TSX

  

 

5. Check the result of step 4. 

Does the test result indicate one of the following failures? 

z

VTEC Switch Failure  

z

VTEC Switch Open  

z

VTEC Switch SIG Line Open  

z

VTEC Switch GND Line Open 

YES: Go to step 6.  

NO: Check for poor connections or loose terminals at the VTEC oil pressure switch. If 
it is OK, replace the VTEC solenoid valve (see VTEC SOLENOID VALVE 
REMOVAL/INSTALLATION ), then, go to step 14 .  

6. Turn the ignition switch OFF.  

7. Disconnect the VTEC oil pressure switch 2P connector.  

8. At the VTEC oil pressure switch, check for continuity between terminals No. 1 and No. 2. 

Is there continuity? 

YES: Go to step 9.  

NO: Replace the VTEC oil pressure switch (see VTEC OIL PRESSURE SWITCH 
REPLACEMENT ), then go to step 13 . 

 

2004 Acura TSX 

2004 ENGINE PERFORMANCE VTEC/VTC - TSX

  

 

Fig. 15: Checking For Continuity Between VTEC Oil Pressure Switch Terminals No. 1 & No. 
2 

9. Turn the ignition switch ON (II).  

10. Measure voltage between VTEC oil pressure switch terminal No. 1 and body ground. 

Is there battery voltage? 

YES: Repair open in the wire between the VTEC oil pressure switch and G101, then go to 
step 13 .  

NO: Go to step 11.  

 

2004 Acura TSX 

2004 ENGINE PERFORMANCE VTEC/VTC - TSX