Circuit Description
The vehicle control module (VCM) and the class 2 data line provide the vehicle speed information to the electronic variable orifice (EVO)/Passlock™ Module. The EVO/Passlock™ module compares the vehicle speed signal received from the vehicle speed sensor (VSS) with the vehicle speed data received from the class 2 data line. The VSS is a permanent magnet sensor that produces an AC signal with varying frequency. The VSS is mounted in the transmission (RWD) or the transfer case (F4WD). The VSS is driven by the output shaft. The VSS produces a pulsing AC voltage when the vehicle speed is greater than 5 km/h (3 mph). The AC voltage and the number of pulses increase with the vehicle speed. The VCM supplies the vehicle speed signal to the instrument cluster and to the EVO/Passlock™ module.
Conditions for Setting the DTC
| • | The vehicle speed sensor message is less than 5 km/h (3 mph). Simultaneously, for 10 seconds, the class 2 vehicle speed message is 10 km/h (6 mph) greater than the VSS message. |
| • | The above conditions have been met for 5 consecutive class 2 samples. |
Action Taken When the DTC Sets
The EVO/Passlock™ module will not send any current to the steering assist control solenoid. This will cause the solenoid valve to retract. The retraction provides maximum fluid flow and full power steering assist at all times.
Conditions for Clearing the DTC
| • | A history DTC will clear after 100 consecutive ignition cycles have occurred without a fault. |
| • | Use a scan tool in order to clear the history and the current DTC(s). |
Diagnostic Aids
- Check for powertrain DTC P0500 or any other vehicle speed related codes. Perform those diagnostic tables first.
- A scan tool will show the vehicle speed when the drive wheels are turning faster than 5 km/h (3 mph). If the drive wheels are not turning, the vehicle speed will not display a signal.
- An intermittent problem may be caused by the following conditions:
- Thoroughly check the EVO/Passlock™ module and the VCM for terminals that have the following conditions:
| • | A poor connection |
| • | A break in the wire insulation that exposes the internal wire |
| • | A wire that is broken inside the insulation |
| • | Any terminals that have backed out |
| • | Broken locks |
| • | Imporperly formed terminals |
| • | Damaged terminals |
| • | Weak terminals that retain tension |
| • | Proper routing |
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
-
This step ensures that you perform the diagnostic system check.
-
This step checks the vehicle speed signal to the VCM.
-
This step ensures that the other systems on the same circuit are receiving a VSS signal.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Did you perform the Diagnostic System Check? | -- | Go to Step 2 | ||
Does the speedometer operate properly? | -- | Go to Step 3 | ||
Did you find any (VCM) VSS codes? | -- | Go to Step 4 | ||
4 | Repair the open in CKT 389 (DK GRN). Refer to Wiring Repairs in Wiring Systems. Did you make a repair? | -- | Go to Step 6 | Go to Step 5 |
5 | Replace the EVO/Passlock™ Module. Refer to Elec Variable Orifice Passlock Module Replacement . Is the replacement complete? | -- | Go to Step 6 | -- |
6 |
Is DTC C0000 current? | -- | Go to Step 1 |
