Vehicle speed information is provided to the transmission control module (TCM) by the vehicle speed sensor (VSS). The VSS is a permanent magnet generator hat is mounted in the transaxle and produce a pulsing voltage whenever vehicle speed is over 5 km/h (3 mph). The A/C voltage level and the number of pulses increase with vehicle speed. The TCM converts the pulsing voltage into km/h (mph) and than supplies the necessary signal to the instrument cluster for speedometer and/or odometer operation and to the cruise control module and multi-function alarm module operation.
The diagnostic trouble code (DTC) will set if there is no input signal.
• | System voltage is between 9.0-18.0 volts. |
• | Road test the vehicle. Refer to Road Test |
Engine speed is greater than 600 RPM.
• | The TCM illuminates the A/T warning lamp when the diagnostic runs and fails |
• | The transmission will default to third gear only. |
• | Line pressure control is set to full throttle. |
The TCM turns OFF the A/T warning lamp when the diagnostic runs and does not fail.
Step | Action | Values | Yes | No |
---|---|---|---|---|
1 | Did you perform the Diagnostic System Check? | -- | Go to Step 2 | |
2 |
Is the voltage with the specified value? | 11-14 volts | Go to Step 3 | Go to Step 5 |
3 |
Caution: 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. Is the voltage greater than or equal to specified value? | 0.5 volts | Go to Step 12 | Go to Step 4 |
4 | Measure the resistance in the VSS signal circuit. Is the resistance greater than the specified value? | 1950Ω | Go to Step 6 | Go to Step 7 |
5 | Repair an open in the VSS ignition circuit. Did you complete the repair? | -- | Go to Step 12 | -- |
6 | Repair an open in the VSS signal circuit. Did you complete the repair? | -- | Go to Step 12 | -- |
7 | Is the resistance value within the specified value? | 1,300-1,950Ω | Go to Step 8 | Go to Step 9 |
8 | Inspect the VSS signal circuit for a short to ground or for being shorted together and repair as necessary. Did you complete the repair? | -- | Go to Step 12 | -- |
9 |
Is the resistance value within the specified value? | 1,300-1,950Ω | Go to Step 11 | Go to Step 10 |
10 | Replace the VSS. Did you complete the repair? | -- | Go to Step 12 | -- |
11 | Replace the TCM. Did you complete the repair? | -- | Go to Step 12 | -- |
12 |
Does the DTC reset? | -- | Go to Step 2 | System OK |