Circuit Description
A toothed wheel mounted on the output shaft of the transmission generates an AC voltage pulse as it moves past the Vehicle Speed Sensor (VSS). The VSS contains a permanent magnet surrounded by a coil of wire, which produces a magnetic field. The toothed wheel interrupts the magnetic field this generates an AC voltage pulse. As the vehicle speed increases the AC voltage pulse rate also increases.
The PCM supplies this signal to the BCM and the instrument cluster.
Conditions for Running the DTC
| • | DTCs P0107, P0108, P0117, P0118, P0506, P0507, P1120, P1220, P1221 are not set. |
| • | ECT is greater than 35°C (95°F) |
| • | Engine speed is greater than 1000 RPM |
| • | TP sensor angle is greater than 10% |
| • | MAP is greater than 40 kPa when A/C is OFF |
| • | MAP is greater than 45 kPa when A/C is ON |
| • | All conditions met for 2 seconds. |
Conditions for Setting the DTC
The PCM detects vehicle speed at 0 km/h (0 mph) for 50 seconds.
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A last test failed, or current DTC, clears when the diagnostic runs and does not fail. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Use a scan tool in order to clear the MIL and the DTC. |
Diagnostic Aids
Important: Remove any debris from the PCM\TAC module connector surfaces before servicing the PCM\TAC module. Inspect the PCM\TAC module connector gaskets when diagnosing/replacing the modules. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM\TAC modules.
Inspect all of the circuits to the PCM and the VSS. Inspect the terminal connections at the VSS harness connector and at the PCM harness connector. If all of the circuits and connections are OK, replace the PCM.
For an intermittent, refer to Symptoms .
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
|
Notice: Support the lower control arms in the normal horizontal position in order to avoid damage to the drive axles. Do not operate the vehicle in gear with the wheels hanging down at full travel.
Does the scan tool indicate a vehicle speed above the specified value? | 15 mph (24 kph | Refer to Diagnostic Aids | ||
3 |
Slowly bring the engine speed to 1500 rpm and hold. Does the DMM indicate a voltage above the specified value? | 1.20 V | ||
4 |
Is the test lamp illuminated? | -- | ||
5 |
Is the voltage above the specified value? | .2 V | ||
6 | Check the VSS high circuit for an open or short to ground. Did you find and correct the condition? | -- | ||
7 | Repair the short to voltage on the VSS high circuit. Is the action complete? | -- | -- | |
8 | Repair the open/high resistance in the VSS high circuit. Is the action complete? | -- | -- | |
9 |
Important: Check the reluctor wheel on the transmission output shaft for damage. Refer to Manual Transmission . Replace the VSS. Refer to Driveline/Axle . Is the action complete? | -- | -- | |
10 | Repair the open in the VSS low circuit. Is the action complete? | -- | -- | |
11 |
Important : Program the replacement PCM. Refer to Powertrain Control Module/Throttle Actuator Control Module Replacement . Replace the PCM. Is the action complete? | -- | -- | |
12 |
Does the scan tool indicate that this test ran and passed? | -- | ||
13 | Select the Capture Info option and the Review Info option using the scan tool. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to the applicable DTC table | System OK |
