GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2004 🢒 Savana - AWD 🢒 Brakes 🢒 Antilock Brake System 🢒 DTC C0245

Circuit Description

As the front wheels spin, each wheel speed sensor produces an AC signal. The electronic brake control module (EBCM) uses the frequency of the AC signals to calculate each wheel speed. The powertrain control module (PCM) converts the signal from the vehicle speed sensor (VSS) to a 128k pulses/mile signal. The EBCM uses the vehicle speed signal from the PCM to calculate the rear wheel speed.

Conditions for Running the DTC
    • The ignition is ON.
    • The vehicle speed is greater than 8 km/h (4 mph).
    • No brake application or deceleration is detected.
    • No wheel slip is detected.
    • No turning maneuvers are detected.

Conditions for Setting the DTC
    • At least one wheel speed sensor signal is 15% less than or greater than other wheel speed sensor signals.
    • All of the Conditions for Running and Setting the DTC are present for a cumulative time of 3 minutes during a single ignition cycle.

Action Taken When the DTC Sets
    • The EBCM disables the ABS/DRP.
    • The ABS indicator turns ON.
    • The brake warning indicator turns ON.

Conditions for Clearing the DTC

The Conditions for Setting the DTC are no longer present and you use the scan tool Clear DTCs function.

Diagnostic Aids

Installing one tire of significantly different size on the vehicle causes this DTC to set. 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 or vehicle speed sensor if the tires and the EBCM and PCM calibrations are OK.

Test Description

The number below refers to the step number on the diagnostic table.

  1. If the front tires are not the same size as the rear tires, the EBCM calibration must match the FRONT tire size and the PCM calibration must match the REAR tire size.

Step

Action

Yes

No

1

Did you perform the ABS Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - ABS

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

4

Verify the EBCM and the PCM both have the correct tire size calibration. Use the scan tool in order to view the EBCM tire size calibration or perform the Tire Size Calibration procedure and refer to Service Programming System (SPS) in Programming.

Did you find and correct the condition?

Go to Step 5

Go to Diagnostic Aids

5
  1. Use a scan tool in order to clear the DTCs.
  2. Operate the vehicle for at least 3 minutes within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK