Vehicle Speed Signal Circuit Troubleshooting
Vehicle Speed Signal Circuit TroubleshootingSpecial Tools Required
Test harness 07LAJ-PT3020A
M/T
- Troubleshoot ECM DTCs first.
- Before testing, inspect the No. 4 (10 A) and No. 10 (7.5 A) 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 probe of an Ohmmeter. Cover the white (C) and green (D) test harness leads with protective tape (E).
4. Check for continuity between the RED test harness clip and body ground.
Is there continuity?
YES - Go to step 5.
NO - Repair open in the BLK wire between the VSS andG101.
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. Connect the test harness to the VSS.
7. Turn the ignition switch ON (II).
Is there battery voltage?
YES - Go to step 8.
NO - Repair open in the BLK/YEL wire between the VSS and the under-dash fuse/relay box or repair poor ground or open in BLK wire between VSS and G101.
8. Disconnect the WHT test harness clip (B).
9. Disconnect the test harness from the VSS.
10. Connect the GRN test harness clip (D) to the positive probe of a voltmeter.
Is there 5 V or battery voltage?
YES - Go to step 11.
NO - Repair short or open in the BLU/WHT [WHT/GRN] wire between the VSS, the gauge assembly, the cruise control and the ECM.
11. Turn the ignition switch OFF.
12. Connect the other test harness connector (A) to the VSS (B).
13. Raise the front of the vehicle, and make sure it is securely supported.
14. Put the vehicle in neutral with the ignition switch ON (II).
15. Slowly rotate one wheel with the other wheel blocked.
Does the voltage pulse from 0 to about 5 V or battery voltage?
YES - Go to step 16.
NO - Replace the VSS.
16. Disconnect the gauge assembly connector A (22P).
17. Touch the voltmeter positive probe to the gauge assembly A4 terminal, and connect the negative probe to body ground.
18. Slowly rotate one wheel with the other wheel blocked.
Does the voltage pulse from 0 to about 5 V or battery voltage?
YES - Replace the speedometer assembly.
NO - Repair open in the BLU/WHT [WHT/GRN] wire between the VSS and the speedometer.
A/T
Before testing, check the No. 9 (10 A) fuse in the under-hood fuse/relay box and the No. 10 (7.5 A) fuse in the under-dash fuse/relay box.
1. Start the engine, and check the malfunction indicator lamp (MIL).
Does the MIL come and stay on?
YES - Troubleshoot the PCM DTC, and recheck.
NO - Go to step 2.
2. Check the multiplex control unit DTC.
Is the DTC indicated?
YES - Troubleshoot the DTC, and recheck.
NO - Inspect the connector and socket terminals of the gauge assembly connectors. If the terminals look OK, substitute a known-good gauge assembly and retest. If the problem is fixed, replace the gauge assembly. If the problem is not fixed, replace the PCM.