Vehicle Speed Signal Circuit Troubleshooting

Special Tools Required:
Test Harness (  07LAJ-PT3020A)
 



M/T:

Before testing, inspect the No. 3 (7.5A) fuses in the under-dash fuse/relay box.

1.Disconnect the 3P connector from the  vehicle speed sensor (VSS) (A).

 

2.Connect the test harness only to the engine wire harness.

3.Connect the RED test harness clip (B) to the positive prove of an ohmmeter. Cover the white (C) and green (D) test harness with protective tape (E).

4.Check for continuity between the RED test harness clip and body ground.

Is there continuity?


YES - Go to 5.


NO - Repair open in the BLK wire between the  VSS and G101.n

5.Connect the WHT test harness clip (B) to the positive probe of a voltmeter, and connect the RED test harness clip (C) to the negative probe.

 

6.Turn the ignition switch ON (II).

Is there battery voltage?


YES - Go to 7.


NO - Repair open in the BLK/YEL wire between the  VSS and the under-dash fuse/relay box.n


7.Disconnect the WHT test harness clip (B).

8.Connect the GRN test harness clip (D) to the positive probe of a voltmeter.

 

Is there 5 V or more?


YES - Go to 9.


NO - Repair short in the BLU/WHT wire between the  VSS and the cruise control unit, or the  ECM.n

9. Turn the ignition switch OFF.

10.Connect the other test harness connector (A) to the VSS (B).

 

11.Raise the front of the vehicle, and make sure it is securely supported.

12.Put the vehicle in neutral with the ignition switch ON (II).

13.Slowly rotate one wheel with the other wheel blocked.

Does voltage pulse from 0 to about 5 V or more?


YES - Go to 14.


NO - Replace the  VSS.n

14.Disconnect the 22P connector ‘‘A'' from the gauge assembly.

 

15.Touch a probe to the BLU/YEL [BLU/WHT] wire, and connect it to body ground through a voltmeter.

16.Slowly rotate one wheel with the other wheel blocked.

Does the voltmeter indicate pulsing voltage?


YES - Replace the speedometer assembly.n


NO - Repair open in the BLU/YEL [BLU/WHT] wire between the  VSS and the speedometer.n

CVT:

Before testing:


1.Raise the vehicle, and make sure it is securely supported.

2.Disconnect the 30P connector C from the gauge assembly.

3.Connect the C10 terminal to the positive probe of a voltmeter, and connect the negative probe to body ground. To prevent damage to the gauge assembly, lay the gauge assembly on a shop rag.

 

4.Put the vehicle in neutral with the ignition switch ON (II).

5.Slowly rotate (over 3 km/h (2 mph)) one wheel with the other wheel blocked.

Does voltage pulse from 0 to approx. 5 V or more?


YES - Replace the gauge assembly.n


NO - Turn the ignition switch OFF, and go to 6.

6.Connect the No. 9 terminal of the PCM 31P connector E to the positive probe of a voltmeter, and connect the negative probe to body ground.

 

7.Put the vehicle in neutral with the ignition switch ON (II).

8.Slowly rotate (over 3 km/h (2 mph)) on wheel with the other wheel blocked.

Does voltage pulse from 0 to approx. 5 V or more?


YES - Repair open in the BLU/YEL wire between the gauge assembly and the  PCM.n


NO - Turn the ignition switch OFF, and go to 9.


9.Disconnect the 31P connector E from the PCM.

10.Check for continuity between No. 25 terminal and body ground.

 

Is there continuity?


YES - Repair short to ground in the BLU/YEL wire between the  PCM and the gauge assembly.n


NO - Check for these problems:

  • Bent, loose or corroded terminals.
  • A faulty  PCM.n