• | 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 or High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Left Front Sensor Signal | C0035 00 | C0035 00 | C0035 00 | C0035 0F C0035 18 |
Left Front Sensor Low Reference | C0035 00 | C0035 00 | C0035 00 | C0035 0F C0035 18 |
Right Front Sensor Signal | C0040 00 | C0040 00 | C0040 00 | C0040 0F C0040 18 |
Right Front Sensor Low Reference | C0040 00 | C0040 00 | C0040 00 | C0040 0F C0040 18 |
Left Rear Sensor Signal | C0045 00 | C0045 00 | C0045 00 | C0045 0F¹ C0045 18 |
Left Rear Sensor Low Reference | C0045 00 | C0045 00 | C0045 00 | C0045 0F¹ C0045 18 |
Right Rear Sensor Signal | C0050 00 | C0050 00 | C0050 00 | C0050 0F¹ C0050 18 |
Right Rear Sensor Low Reference | C0050 00 | C0050 00 | C0050 00 | C0050 0F¹ C0050 18 |
¹Damaged rear wheel speed sensor ring can cause code to set. |
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.
• | The ignition is ON. |
• | Ignition voltage is greater than 8 volts. |
• | The ignition is ON. |
• | Ignition voltage is greater than 8 volts. |
• | The brake pedal is not pressed. |
• | A DTC is not set for the other wheel speed circuit on the same axle. |
• | The ignition is ON. |
• | Ignition voltage is greater than 8 volts. |
• | The brake pedal is not pressed. |
• | No other wheel speed circuit DTCs are set. |
• | At least 2 other wheel speeds are not 0 km/h. |
• | An open is detected on the wheel speed sensor signal circuit. |
• | A short to ground is detected on the wheel speed sensor signal circuit. |
• | A short to voltage is detected on the wheel speed sensor signal circuit. |
The EBCM detects a rapid variation in the wheel speed. The wheel speed changes by 20 km/h (12 mph) or more in 0.01 second. The change must occur 3 times with no more than 0.2 second between occurrences.
• | One wheel speed is 0 km/h. |
• | The remaining wheel speeds are greater than 8 km/h (5 mph). |
• | The difference between the remaining wheel speeds is less than 11 km/h (7 mph) from each other. |
OR
• | The 2 wheel speed sensor inputs are 0 and DTCs are set. |
• | The 2 suspect wheel speeds equal zero for 6 seconds. |
• | The other wheel speeds are greater than 16 km/h (10 mph). |
• | The other wheel speeds are within 11 km/h (7 mph) of each other. |
• | 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 dynamic rear proportion (DRP) does not function optimally. |
• | The ABS indicator turns ON. |
• | The traction control indicator turns ON. |
• | The driver information center (DIC) displays the Service Stability System message. |
• | The condition for setting the DTC is no longer present and the DTC is cleared with a scan tool. |
• | The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles. |
• | A damaged rear wheel speed sensor ring can cause failure type byte 04 (Erratic Signal) to set. |
• | If 2 or more wheel speed sensors are inoperative diagnose each wheel speed sensor individually. |
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:
Antilock Brake System Schematics
Antilock Brake System Connector End Views
Scan Tool Data List for EBCM
With scan tool installed drive the vehicle in a straight line at a speed greater than 8 km/h (5 mph), all wheel speed sensors should read the same miles per hour.
Important: It is recommend that Component Testing is performed before Circuit Testing when diagnosing wheel speed sensors.
⇒ | If over 0 volt, repair short to voltage in sensor signal circuit or the low reference circuit. |
⇒ | If less than infinite ohms, repair short to ground in the sensor signal or the low reference circuit. |
⇒ | If greater than 1350 ohms test for an open/high resistance in the circuit or faulty wheel speed sensor. |
⇒ | If less than 850 ohms test for a short between the circuits or faulty wheel speed sensor. |
⇒ | If the resistance is not between 850-1350 ohms replace the faulty wheel speed sensor. |
⇒ | If the AC voltage is less than 100 mv replace the wheel speed sensor. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for EBCM replacement, setup, and programming |