C0040

DTC C0035 or C0040

Circuit Description
As the 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.

Conditions for Running the DTC
Both of the conditions listed below may be required to set the DTC.
^ The ignition is ON.
^ The vehicle speed is greater than 13 km/h (8 mph).

Conditions for Setting the DTC
Any of the following occurrences may cause the DTC to set.
^ The EBCM detects an open or shorted wheel speed sensor circuit for 500 milliseconds.
^ The EBCM detects the absence of a wheel speed sensor signal for 5 seconds. If more than one absent wheel speed sensor signal is detected, the condition must be present for 120 seconds to set DTCs.
^ The EBCM detects an erratic wheel speed sensor signal for 200 milliseconds.

Action Taken When the DTC Sets
If equipped, the following actions may occur.
^ The EBCM disables the ABS/TCS/VSES and may disable the DRP if more than one wheel speed sensor DTC is set.
^ The ABS indicator turns ON.
^ The brake warning indicator may turn ON.
^ The stability indicator turns ON.
^ An ECE 13 response may occur.

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

Steps 1-7:

Steps 8-10:

Thoroughly inspect connections or circuitry that may cause an intermittent malfunction.

If the customer's concern is that the ABS indicator is on only during humid conditions such as rain, snow or vehicle wash, thoroughly inspect the wheel speed sensor circuits for signs of water intrusion. Use the following procedure in order to help isolate the problem area:
1. Spray the suspected area with a 5 percent salt water solution.
2. Operate the vehicle at a speed greater than 13 km/h (8 mph) for at least 30 seconds. Repair or replace the suspect harness if the DTC sets.