Circuit Description
The rate at which the wheel/vehicle speed sensor ring makes a full 360° rotation is directly related to the circumference of the tire(s).
Conditions for Running the DTC
| • | The ignition is ON. |
| • | The vehicle is moving at a speed greater than 24 km/h (15 mph) and less than 80 km/h (50 mph). |
Conditions for Setting the DTC
The EBCM detects that one speed sensor signal is at least 10% greater than or less than the other speed sensor signals.
Action Taken When the DTC Sets
| • | The ABS, BRAKE and TRACTION OFF (if equipped with traction control) indicators are commanded on. |
| • | The ABS, DRP and Traction Control (if equipped) are disabled for the remainder of the ignition cycle. |
Conditions for Clearing the DTC
| • | The condition(s) responsible for setting the DTC are no longer present. |
| • | A scan tool is used in order to clear the DTC. |
Diagnostic Aids
Installing one tire of significantly different size on the vehicle will set DTC C0238. Operating the vehicle with a tire that has very low air pressure may also set this DTC. Inspect the vehicle for an incorrect or damaged wheel speed sensor(s) or vehicle speed sensor if the tires and the EBCM and VCM/PCM calibrations are OK.
Test Description
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the ABS Diagnostic System Check? | -- | Go to Step 2 | Go to Diagnostic System Check |
2 | Inspect both of the front tires on the vehicle to ensure that both tires are of equal size. Are both of the front tires of equal size? | -- | Go to Step 3 | Go to Diagnostic Aids |
3 | Inspect both of the rear tires on the vehicle to ensure that both tires are of equal size. Are both of the rear tires of equal size? | -- | Go to Step 4 | Go to Diagnostic Aids |
Use a scan tool in order to verify that the EBCM and the VCM/PCM both have the correct tire size calibration. Refer to Scan Tool Diagnostics and VCM Replacement/Programming in Engine Controls-4.3L or Powertrain Control Module Replacement in Engine Controls-4.8L, 5.3L, and 6.0L. Did you find and correct the condition? | -- | Go to Step 5 | Go to Diagnostic Aids | |
5 |
Does the DTC set? | -- | Go to Step 2 | System OK |
