DTC 28

DTC 28

Step 1-5:

Step 6-14:

Circuit Description
As the wheel spins, the wheel speed sensor produces an Alternating Current (AC) signal. The Electronic Brake Control Module (EBCM) uses the frequency of the AC signal to calculate the wheel speed.

Conditions for Running the DTC
- The ignition is in the ON position.
- Vehicle speed of 12 km/h (8 mph) or more.

Conditions for Setting the DTC
The EBCM detects a wheel speed sensor frequency error.

Action Taken When the DTC Sets
The following actions occur:
- The EBCM disables the Antilock Brake System (ABS) and traction control system for the duration of the ignition cycle.
- The ABS and TRAC OFF indicators turn ON.

Conditions for Clearing the DTC
The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.

Diagnostic Aids
Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction.

The following are possible causes of the malfunction:
- A malfunctioning wheel speed sensor
- A malfunctioning wheel speed sensor ring
- A short to ground or a short to voltage in the wheel speed sensor circuitry
- An open or high resistance in the wheel speed sensor circuitry
- An internal EBCM malfunction

If an intermittent malfunction exists, refer to Testing for Intermittent and Poor Connections Diagnostic Aids.

Test Description
The numbers in the images, refer to the step numbers on the diagnostic table.
6. This step tests the front wheel speed sensors for proper resistance value.
7. This step tests the front wheel speed sensors for proper resistance value.
8. This step tests the wheel speed sensor circuits for a short, open or high resistance.