Acura TSX / Honda Accord CL. Manual - part 955

3. Check the OBD STATUS in DTCs MENU for a pass/fail test of code P0718. 

Did the result indicate a fall? 

YES: Go to step 4.  

NO: Intermittent failure, the system is OK at this time. Check for poor connections or loose 
terminals at the mainshaft speed sensor and PCM. If the tester indicates NOT COMPLETE, 
return to step 2 and recheck.  

4. Turn the ignition switch OFF.  

5. Disconnect the mainshaft speed sensor connector, and inspect the connector and connector terminals to be 

sure they are making good contact. 

Are the connector terminals OK? 

YES: Go to step 6.  

NO: Repair the connector terminals, then go to step 6.  

6. Connect the mainshaft speed sensor connector.  

7. Test-drive the vehicle for several minutes, and check the OBD STATUS in DTCs MENU for a pass/fail 

test of code P0718. 

Did the result indicate a fail? 

YES: Go to step 8.  

NO: The problem has been corrected. If the tester indicates NOT COMPLETE, return to step 
7 and recheck.  

8. Turn the ignition switch OFF.  

9. Jump the SCS line with the HDS.  

10. Disconnect PCM connector C (22P).  

11. Disconnect the mainshaft speed sensor connector.  

12. Check for continuity between mainshaft speed sensor connector terminal No. 2 and body ground. 

Is there continuity? 

YES: Repair short to ground in the wire between PCM connector terminal C19 and the 
mainshaft speed sensor connector, then go to step 19 .  

NO: Go to step 13.  

 

2004 Acura TSX 

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed

  

 

Fig. 130: Checking For Continuity Between Mainshaft Speed Sensor Connector Terminal No. 
2 & Body Ground 

13. Connect PCM connector C (22P).  

14. Turn the ignition switch ON (II).  

15. Measure the voltage between mainshaft speed sensor connector terminal No. 2 and body ground. 

Is there about 5 V? 

 

2004 Acura TSX 

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed

  

 

YES: Replace the mainshaft speed sensor (see MAINSHAFT SPEED SENSOR 
REPLACEMENT ), then go to step 19 .  

NO: Go to step 16.  

Fig. 131: Measuring The Voltage Between Mainshaft Speed Sensor Connector Terminal No. 2 
& Body Ground 

16. Turn the ignition switch OFF.  

 

2004 Acura TSX 

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed

  

 

17. Disconnect PCM connector C (22P).  

18. Check for continuity between PCM connector terminal C19 and mainshaft speed sensor connector 

terminal No. 2. 

Is there continuity? 

YES: Update the PCM if it does not have the latest software, or substitute a known-good 
PCM (see PCM UPDATING & SUBSTITUTION FOR TESTING ), then recheck. If the 
symptom/indication goes away with a known-good PCM, replace the original PCM.  

NO: Repair open in the wire between PCM connector terminal C19 and the mainshaft speed 
sensor, then go to step 19.  

Fig. 132: Checking For Continuity Between PCM Connector Terminal C19 & Mainshaft 
Speed Sensor Connector Terminal No. 2 

19. Clear the DTC with the HDS.  

20. Test-drive the vehicle for several minutes in the D position in all five gears.  

21. Check the OBD STATUS in DTCs MENU for a pass/fail test of code P0718. 

Did the result indicate a pass? 

YES: The problem has been corrected.  

NO: Return to step 1 and recheck.  

DTC P0721: PROBLEM IN COUNTERSHAFT SPEED SENSOR CIRCUIT 

 

2004 Acura TSX 

2004 AUTOMATIC TRANSMISSIONS Diagnosis - MCTA 5-Speed