• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Left Front Sensor Voltage Signal | C0035, C0037 | C0035, C0037 | C0035, C0037 | C0036 |
Left Front Sensor Low Reference Signal | C0035, C0037 | C0035, C0037 | C0035, C0037 | C0036 |
Right Front Sensor Voltage Signal | C0040, C0042 | C0040, C0042 | C0040, C0042 | C0041 |
Right Front Sensor Low Reference Signal | C0040, C0042 | C0040, C0042 | C0040, C0042 | C0041 |
Left Rear Sensor Voltage Signal | C0045, C0047 | C0045, C0047 | C0045, C0047 | C0046 |
Left Rear Sensor Low Reference Signal | C0045, C0047 | C0045, C0047 | C0045, C0047 | C0046 |
Right Rear Sensor Voltage Signal | C0050, C0052 | C0050, C0052 | C0050, C0052 | C0051 |
Right Rear Sensor Low Reference Signal | C0050, C0052 | C0050, C0052 | C0050, C0052 | C0051 |
As the wheel spins, the wheel speed sensor (WSS) produces an AC signal. The electronic brake control module (EBCM) uses the frequency of the AC signal to calculate the wheel speed.
Ignition ON.
• | DTCs C0035, C0040, C0045, or C0050 are not set. |
• | The brake pedal is not pressed. |
• | The ABS is not active. |
• | At least two wheel speeds are not 0 km/h. |
• | A short to ground, or an open/high resistance is detected on the wheel speed sensor signal circuit. |
• | A short to B+, short to ground or an open/high resistance is detected on the low reference circuit. |
The EBCM detects 3 irratic readings from a wheel speed sensor.
• | The suspect wheel speed equals zero. |
• | The other wheel speeds are greater than 8 km/h (5 mph). |
• | The other wheel speeds are within 11 km/h (7 mph) of each other. |
If equipped, the following actions occur:
• | The EBCM disables the antilock brake system (ABS)/traction control system (TCS)/vehicle stability enhancement system (VSES) for the duration of the ignition cycle. |
• | The EBCM disables the dynamic rear proportion (DRP). |
• | The ABS indicator illuminates. |
• | The Traction Control indicator illuminates. |
• | The driver information center (DIC) displays the Service Stability System message. |
• | The condition for the DTC is no longer present. |
• | The EBCM clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles. |
If the customer comments that the ABS indicator is ON only during moist environmental conditions (rain, snow, vehicle wash, etc.), inspect the wheel speed sensor wiring for signs of water intrusion. If the DTC is not current, clear all DTCs and simulate the effects of water intrusion by using the following procedure:
A possible cause of this DTC is electrical magnetic interference.
Antilock Brake System Schematics
Control Module References for scan tool information
Observe the scan tool Wheel Speed Sensor parameter. The reading should be the same on all sensors when driving in a straight line at a speed greater than 20 km/h (13 mph).
Important: Component Testing is performed before Circuit Testing when diagnosing wheel speed sensors.
• | LF Sensor circuit terminal 28 |
• | RF Sensor circuit terminal 24 |
• | LR Sensor circuit terminal 12 |
• | RR Sensor circuit terminal 43 |
⇒ | If greater than the specified value, test the low reference circuit for a short to voltage. If the circuit tests normal, test or replace the wheel speed sensor. |
• | LF Sensor circuit terminal 27 |
• | RF Sensor circuit terminal 39 |
• | LR Sensor circuit terminal 13 |
• | RR Sensor circuit terminal 42 |
⇒ | If greater than the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, test or replace the wheel speed sensor. |
• | LF Sensor circuit terminal 28 |
• | RF Sensor circuit terminal 24 |
• | LR Sensor circuit terminal 12 |
• | RR Sensor circuit terminal 43 |
⇒ | If less than the specified value, test the low reference circuit for a short to ground. If the circuit tests normal, test or replace the wheel speed sensor. |
• | LF Sensor circuit terminal 27 |
• | RF Sensor circuit terminal 39 |
• | LR Sensor circuit terminal 13 |
• | RR Sensor circuit terminal 42 |
⇒ | If less than the specified value, test the signal circuit for a short to ground. If the circuit tests normal, test or replace the wheel speed sensor. |
• | LF Sensor circuit terminal 28 at the EBCM harness connector and terminal B at the WSS harness connector. |
• | RF Sensor circuit terminal 24 at the EBCM harness connector and terminal B at the WSS harness connector. |
• | LR Sensor circuit terminal 12 at the EBCM harness connector and terminal B at the WSS harness connector. |
• | RR Sensor circuit terminal 43 at the EBCM harness connector and terminal B at the WSS harness connector. |
⇒ | If greater than the specified value, test the low reference circuit for an open or high resistance. If the circuit tests normal, test or replace the wheel speed sensor. |
• | LF Sensor circuit terminal 27 at the EBCM harness connector and terminal A at the WSS harness connector. |
• | RF Sensor circuit terminal 39 at the EBCM harness connector and terminal A at the WSS harness connector. |
• | LR Sensor circuit terminal 13 at the EBCM harness connector and terminal A at the WSS harness connector. |
• | RR Sensor circuit terminal 42 at the EBCM harness connector and terminal A at the WSS harness connector. |
⇒ | If greater than the specified value, test the voltage signal circuit for an open or high resistance. If the circuit tests normal, test or replace the wheel speed sensor. |
⇒ | If not within the specified range, replace the wheel speed sensor. |
⇒ | If less than the specified value, replace the appropriate wheel speed sensor. |
⇒ | If less than the specified range, replace the wheel speed sensor. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for EBCM replacement, setup and programming |