Without RPO JL4

Antilock Brake System

Diagnostic Information and Procedures

DTC C0221-C0227 (W/O JL4)

Circuit Description

As the wheel spins, the wheel speed sensor produces an AC signal. The EBCM uses the frequency of the AC signal to calculate the wheel speed.

Conditions for Running the DTC

C0221 and C0225

The ignition is ON.

C0222, C0223, C0226 and C0227

The vehicle speed is greater than 32 km/h (20 mph) when the brake is applied or 19 km/h (12 mph) when the brake is released.

Conditions for Setting the DTC

C0221 and C0225

The EBCM detects an open or shorted wheel speed sensor or wheel speed sensor circuit for 500 milliseconds.

C0222 and C0226

The corresponding wheel speed sensor signal is less than 6 km/h (4 mph) for 5 seconds, or 120 seconds in order to set both DTC's.
C0223 and C0227
The EBCM detects an erratic signal from the corresponding wheel speed sensor for 105 milliseconds.

Action Taken When the DTC Sets

C0221, C0225

If equipped, the following actions occur:
- The EBCM disables the ABS/TCS.
- The ABS indicator turns ON.
- The TRACTION OFF indicator turns ON.

C0222, C0223, C0226, and C0227

If equipped, the following actions occur:
- The EBCM disables the ABS/TCS and may disable DRP.
- The ABS indicator turns ON.
- The TRACTION OFF indicator turns ON.
- The red Brake warning indicator may turn ON.

Conditions for Clearing the DTC

- Repair the condition responsible for setting the DTC.
- Use a scan tool in order to clear the DTC.
- After the DTC is cleared and the ignition is ON, the ABS indicator may remain ON until the EBCM completes a power-up self-test. This test concludes when the vehicle reaches a speed greater than 13 km/h (8 mph) and the wheel speeds are verified by the EBCM.

Diagnostic Aids

Operating the vehicle on extremely rough terrain can set DTC C0223, C0227 or C0229 even if the system is functioning normally.
Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Refer to Testing for Intermittent and Poor Connections, Connector Repairs, Testing for Electrical Intermittents and to Wiring Repairs in Wiring Systems.
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 % salt-water solution.
2. Drive the vehicle at a speed greater than 19 km/h (12 mph) for at least 30 seconds.
Repair or replace the suspect harness if the DTC sets.

Test Description

The numbers below refer to the step numbers on the diagnostic table.
3. Measure the resistance of the wheel speed sensor in order to determine if the sensor has a valid resistance value.
4. Ensures that the wheel speed sensor is generating a valid AC voltage output.

DTC C0221-C0227 (W/O JL4) Steps 1 - 8:

DTC C0221-C0227 (W/O JL4) Steps 9 & 10: