Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Left Front Sensor Signal | C0035 00 | C0035 00 | C0035 00 | C0035 0F, 18 |
Left Front Sensor Low Reference | C0035 00 | C0035 00 | C0035 00 | C0035 0F, 18 |
Right Front Sensor Signal | C0040 00 | C0040 00 | C0040 00 | C0040 0F, 18 |
Right Front Sensor Low Reference | C0040 00 | C0040 00 | C0040 00 | C0040 0F, 18 |
Left Rear Sensor Signal | C0045 00 | C0045 00 | C0045 00 | C0045 0F, 18 |
Left Rear Sensor Low Reference | C0045 00 | C0045 00 | C0045 00 | C0045 0F, 18 |
Right Rear Sensor Signal | C0050 00 | C0050 00 | C0050 00 | C0050 0F, 18 |
Right Rear Sensor Low Reference | C0050 00 | C0050 00 | C0050 00 | C0050 0F, 18 |
The wheel speed sensor receives a 12-volt power supply voltage from the electronic brake control module (EBCM) and provides an output signal to the EBCM. As the wheel spins, the wheel speed sensor sends the EBCM a DC square wave signal. The EBCM uses the frequency of the square wave signal to calculate the wheel speed.
• | The ignition is ON. |
• | Ignition voltage is greater than 9.5 volts. |
• | The ignition is ON. |
• | Ignition voltage is greater than 9.5 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 9.5 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 2km/h (1.2 mph) . |
• | The remaining wheel speeds are greater than 10 km/h (6.2 mph). |
• | The difference between the remaining wheel speeds is less than 8 km/h (5 mph) from each other for 180 seconds. |
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 15 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) Control System for the duration of the ignition cycle. |
• | ABS indicator turns ON. |
• | Driver information center (DIC) displays the ABS FAULT message. |
• | If both rear wheel speed DTCs are set, the dynamic rear proportioning (DRP) is disabled and the Brake Warning indicator turns ON. |
• | 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. |
• | The ABS telltale will remain on until a vehicle speed of 13 kmp (8 mph) or greater is achieved, unless the scan tool is used to clear the DTC. |
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
With scan tool installed drive the vehicle in a straight line at a speed greater than 10 km/h (6 mph), all wheel speed sensors should read the same speed.
Note: It is recommend that Component Testing is performed before Circuit Testing when diagnosing wheel speed sensors.
Note: Performing Circuit Testing with EBCM connector disconnected and key on will cause U codes to set. Clear DTCs after performing the test.
⇒ | If voltage is below 7.5 check for a short to ground, open or replace EBCM. |
⇒ | If over 0 volts, repair short to voltage in the wheel speed sensor signal circuit or the wheel speed sensor supply voltage circuit. |
⇒ | If less than infinite ohms, repair short to ground in the sensor signal or the low reference circuit. |
⇒ | If less than infinite ohms, repair short between the wheel speed sensor signal circuit and the wheel speed sensor low reference circuit. |
⇒ | If the If voltage is below 7.5 check for a short to ground, open or replace EBCM. |
⇒ | If the low amperage output of the wheel speed sensor signal circuit is below 4 mA or above 8 mA replace the wheel speed sensor. |
⇒ | If the high amperage output of the wheel speed sensor signal circuit is below 12 mA or above 16 mA replace the wheel speed sensor. |
Perform the Diagnostic System Check - Vehicle after completing the diagnostic procedure.
Control Module References for EBCM and BPMV replacement, setup, and programming