Acura TSX / Honda Accord CL. Manual - part 639

Fig. 19: Checking For Continuity Between ECM/PCM Connector Terminal B6 & Body 
Ground 

10. Replace the VTEC solenoid valve (see VTEC SOLENOID VALVE REMOVAL/INSTALLATION ). 

11. Reconnect all connectors.  

12. Turn the ignition switch ON (II).  

13. Reset the ECM/PCM with the HDS.  

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

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

16. Check for Temporary DTCs or DTCs in the DTCs MENU with the HDS. 

Are any Temporary DTCs or DTCs indicated? 

YES: If DTC P2648 is indicated, check for poor connections or loose terminals at the VTEC 
solenoid valve and the ECM/PCM, then go to step 1 . If any other Temporary DTCs or DTCs 

 

2004 Acura TSX 

2004 ENGINE PERFORMANCE VTEC/VTC - TSX

  

 

are indicated, go to the indicated DTC troubleshooting. 

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.  

NO: If the screen indicates FAILED, go to step 1 and recheck. If the screen indicates NOT 
COMPLETED, go to step 15 and recheck.  

18. 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 ).  

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

20. Check for Temporary DTCs or DTCs in the DTCs MENU with the HDS. 

Are any Temporary DTCs or DTCs indicated? 

YES: If DTC P2648 is indicated, check for poor connections or loose terminals at 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 P2649: VTEC SOLENOID VALVE CIRCUIT HIGH VOLTAGE 

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 with no load (in Park or neutral) until the radiator 

fan comes on, then let it idle.  

4. Check for Temporary DTCs or DTCs in the DTCs MENU with the HDS. 

Is DTC P2649 indicated? 

YES: Go to step 5.  

NO: Intermittent failure, system is OK at this time. Check for poor connections or loose 
terminals at the VTEC solenoid valve and the ECM/PCM.  

5. Turn the ignition switch OFF.  

6. Disconnect the VTEC solenoid valve 2P connector.  

7. Measure resistance between VTEC solenoid valve 2P connector terminals No. 1 and No. 2. 

Is there 14-30 ohm? 

YES: Go to step 8.  

NO: Go to step 13 .  

 

2004 Acura TSX 

2004 ENGINE PERFORMANCE VTEC/VTC - TSX

  

 

Fig. 20: Measuring Resistance Between VTEC Solenoid Valve 2P Connector Terminals No. 1 
& No. 2 

8. Check for continuity between VTEC solenoid valve terminal No. 2 and body ground. 

Is there continuity? 

YES: Go to step 9.  

NO: Repair open in the wire between the VTEC solenoid valve and G101, then go to step 
14 .  

 

2004 Acura TSX 

2004 ENGINE PERFORMANCE VTEC/VTC - TSX

  

 

Fig. 21: Checking For Continuity Between VTEC Solenoid Valve Terminal No. 2 & Body 
Ground 

9. Jump the SCS line with the HDS.  

10. Disconnect ECM/PCM connector B (24P).  

11. Connect VTEC solenoid valve 2P connector terminal No. 1 to body ground with a jumper wire. 

 

2004 Acura TSX 

2004 ENGINE PERFORMANCE VTEC/VTC - TSX