DTC C0221-C0227 or C021 W/O JL4
Circuit Description
As the wheel spins, the wheel speed sensor produces an 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
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 DTCs.
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/traction control system (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 dynamic rear proportioning (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 the following:
If the customer 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:
- Spray the suspected area with a 5 percent salt water solution.
- 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.
-
Measure the resistance of the wheel speed sensor in order to determine if the sensor has a valid resistance value.
-
Ensures that the wheel speed sensor is generating a valid AC voltage output.
Step | Action | Values | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Antilock Brake System Schematics Connector End View Reference: Antilock Brake System Connector End Views Important: If DTC C0229 is set, diagnose DTC C0229 before diagnosing any other wheel speed sensor DTCs. | ||||||||||||
1 | Did you perform the ABS Diagnostic System Check? | -- | Go to Step 2 | |||||||||
2 |
Does the DTC set? | 19 km/h (12 mph) | Go to Step 3 | Go to Diagnostic Aids | ||||||||
Does the resistance measure within the specified range? | 700-10,000 ohms | Go to Step 4 | Go to Step 8 | |||||||||
Does the AC voltage measure greater than the specified value? | 100 mV | Go to Step 5 | Go to Step 8 | |||||||||
5 | Inspect for poor connections at the harness connector of the wheel speed sensor. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 6 | ||||||||
6 |
Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 7 | ||||||||
7 | Inspect for poor connections at the harness connector for the EBCM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9 | ||||||||
8 | Replace the wheel speed sensor. Refer to Front Wheel Speed Sensor Replacement . Did you complete the replacement? | -- | Go to Step 10 | -- | ||||||||
9 |
Important: Use the scan tool in order to perform the Tire Size Calibration procedure. Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Did you complete the replacement? | -- | Go to Step 10 | -- | ||||||||
10 |
Does the DTC reset? | -- | Go to Step 2 | System OK | ||||||||
DTC C0221-C0227 or C021 W/JL4
Circuit Description
The system relay is energized when the ignition is ON. The system relay supplies voltage to the valve solenoids and the pump motor. This voltage is referred to as the system voltage. The electronic brake control module (EBCM) microprocessor activates the valve solenoids by grounding the control circuit.
Conditions for Running the DTC
| • | The ignition is ON. |
| • | The vehicle is experiencing an ABS event. |
Conditions for Setting the DTC
The EBCM energizes the right, front dump valve for 9 consecutive seconds.
Action Taken When the DTC Sets
| • | The EBCM disables the ABS/DRP/VSES. |
| • | The TCS operates with engine torque reduction only. |
| • | The ABS indicator turns ON. |
| • | The brake warning indicator turns ON. |
| • | The message center displays the service stability system message. |
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
The most likely cause of this DTC is a mechanical failure that causes a wheel to lock and remain locked. The DTCs may also set, conceivably, when the ABS is activated on surfaces that are nearly impossible to get traction on. If the DTC sets within these conditions, diagnosis of the ABS system is not necessary.
Test Description
The number below refers to the step number on the diagnostic table:
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the ABS Diagnostic System Check? | Go to Step 2 | |
Do the Solenoid Tests show the system to be functioning normally? | Go to Diagnostic Aids | Go to Step 3 | |
3 | Replace the BPMV. Refer to Brake Pressure Modulator Valve Replacement . Did you complete the replacement? | Go to Step 4 | -- |
4 | Use the scan tool in order to perform the necessary Solenoid Tests. Do the Solenoid Tests show the system to be functioning normally? | System OK | Go to Step 3 |
