Diagnostic Aids
| • | An intermittent in the vehicle speed sensor (VSS) circuit may cause an inaccurate speedometer. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
| • | Check for the following DTCs: |
| - | DTC P0502 Vehicle Speed Sensor (VSS) Circuit Low Input and DTC P0503 Vehicle Speed Sensor (VSS) Circuit Intermittent in Automatic Transmission - 4L60-E |
| - | DTC P0500 Vehicle Speed Sensor (VSS) Circuit in Engine Controls - 4.3L |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Instrument Cluster Diagnostic System Check? | -- | Go to Step 3 | |
2 |
Important: If the instrument cluster is completely inoperative, refer to Instrument Cluster Inoperative . Does the vehicles speedometer and the scan tool both display 0 km/h (0 mph)? | -- | Go to Step 4 | Go to Step 3 |
3 | Does the vehicles speedometer approximately agree with the scan tool display? | -- | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 4 |
4 |
Does the DMM display a voltage greater than the specified value? | 9.5V | Go to Step 8 | Go to Step 5 |
5 |
Does the DMM display continuity? | -- | Go to Step 6 | Go to Step 10 |
6 | Test the continuity from the vehicle speed sensor signal (4K) circuit to a good ground. Refer to Testing for Continuity in Wiring Systems. Does the DMM display continuity? | -- | Go to Step 11 | Go to Step 7 |
7 | Test the instrument cluster harness connector for a poor connection to the instrument cluster. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 16 |
8 |
Does the DMM display continuity? | -- | Go to Step 9 | Go to Step 12 |
9 | Test the continuity of the vehicle speed sensor signal (4K) circuit from the PCM/VCM harness connector to a good ground using the DMM J 39200 . Refer to Testing for Continuity in Wiring Systems. Does the DMM display continuity? | -- | Go to Step 13 | Go to Step 14 |
10 | Repair the open vehicle speed sensor signal (4K) circuit from the instrument cluster electrical connector to the in line connector C101. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 17 | -- |
11 |
Important: If you cannot locate a grounded circuit, disconnect each component (one at a time) and see if the grounded condition is caused by a component on the vehicle speed sensor signal (4K) circuit. Refer to Circuit Testing in Wiring Systems. Repair the grounded vehicle speed sensor signal (4K) circuit from the instrument cluster connector to the in line connector C101. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 17 | -- |
12 | Repair the open vehicle speed output (4K) circuit from the PCM/VCM harness connector to the in line connector C101. Refer to Wiring Repairs Did you complete the repair? | -- | Go to Step 17 | -- |
13 | Repair the grounded vehicle speed output (4K) circuit from the PCM/VCM harness connector to the in line connector C101. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 17 | -- |
14 | Test the PCM/VCM harness connector for poor connections. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 15 |
15 |
Important: Program the replacement PCM/VCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls - 2.2L or VCM Replacement/Programming in Engine Controls - 4.3L. Replace the PCM/VCM. Did you complete the replacement? | -- | Go to Step 17 | -- |
16 | Replace the instrument cluster. Refer to Instrument Cluster Replacement . Did you complete the replacement? | -- | Go to Step 17 | -- |
17 | Operate the system in order to verify the repair. Did you find and correct the condition? | -- | System OK | Go to Step 4 |
