Acura TSX / Honda Accord CL. Manual - part 956

1. Record all freeze data, and clear the DTC with the HDS.  

2. Raise the front of the vehicle, make sure it is securely supported, and allow the front wheels to rotate 

freely.  

3. Start the engine, drive the vehicle in the D position, and hold the vehicle at speeds over 30 mph (48 km/h) 

for more than 10 seconds. Slow down and stop the wheels.  

4. Check the OBD STATUS in DTCs MENU for a pass/fail test of code P0721. 

Did the result indicate a fail? 

YES: Go to step 5.  

NO: Intermittent failure, the system is OK at this time. Check for poor connections or loose 
terminals at the countershaft speed sensor and PCM. If the tester indicates NOT 
COMPLETE, return to step 3 and recheck.  

5. Turn the ignition switch OFF.  

6. Jump the SCS line with the HDS.  

7. Disconnect PCM connector A (31P) and countershaft speed sensor connector.  

8. Check for continuity between PCM connector terminals A8 and body ground, and between A9 and body 

ground. 

Is there continuity? 

YES: Go to step 9.  

NO: Repair open in the wire between PCM connector terminals A8, A9 and ground (G101), 
or repair poor ground (G101), then go to step 29 . 

NOTE:

z

Record all freeze data and review General Troubleshooting Information 
(see GENERAL TROUBLESHOOTING INFORMATION ) before you 
troubleshoot.  

z

This code is caused by an electrical circuit problem and cannot be caused 
by a mechanical problem in the transmission.  

 

2004 Acura TSX 

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed

  

 

Fig. 133: Checking For Continuity Between PCM Connector Terminals A8 & Body Ground 
& Between A9 & Body Ground 

9. Connect PCM connector A (31P).  

10. Turn the ignition switch ON (II).  

11. Measure the voltage between countershaft speed sensor connector terminal No. 1 and body ground. 

Is there about 5 V? 

YES: Go to step 12.  

NO: Go to step 23 .  

 

2004 Acura TSX 

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed

  

 

Fig. 134: Measuring The Voltage Between Countershaft Speed Sensor Connector Terminal 
No. 1 & Body Ground 

12. Turn the ignition switch OFF.  

13. Disconnect PCM connector A (31P).  

14. Check for continuity between countershaft speed sensor connector terminal No. 2 and body ground. 

Is there continuity? 

YES: Repair short to ground in the wire between PCM connector terminal A18 and the 
countershaft speed sensor, then go to step 29 .  

NO: Go to step 15.  

 

2004 Acura TSX 

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed

  

 

Fig. 135: Checking For Continuity Between Countershaft Speed Sensor Connector Terminal 
No. 2 & Body Ground 

15. Check for continuity between countershaft speed sensor connector terminal No. 3 and body ground. 

Is there continuity? 

YES: Go to step 16.  

NO: Repair open in the wire between the countershaft speed sensor and ground (G101), or 
repair poor ground (G 101), then go to step 29 . 

 

2004 Acura TSX 

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed