The ABS relay supplies battery voltage to 6 valve solenoids. The electronic brake control module (EBCM) microprocessor applies the grounds needed to activate each solenoid. The low side of each solenoid coil has a feedback circuit to the EBCM microprocessor. When a solenoid is commanded OFF, the feedback voltage is high. When a solenoid is commanded ON, the feedback voltage is low.
• | The ignition is ON. |
• | The vehicle speed is greater than 6 km/h (4 mph). |
The EBCM detects an internal malfunction.
If equipped, the following actions occur:
• | The EBCM disables the DRP/ABS. |
• | The ABS indicator turns ON. |
• | The red brake warning indicator turns ON. |
If equipped, the following actions occur:
• | The EBCM disables the ABS. |
• | The ABS indicator turns ON. |
The conditions for setting the DTC are no longer present and you use the scan tool Clear DTCs function.
An intermittent open/shorted solenoid DTC can be set by several different internal EBCM problems. Replace the EBCM if an open/shorted solenoid DTC continues to set intermittently.
Step | Action | Yes | No |
---|---|---|---|
1 | Did you perform the ABS Diagnostic System Check? | Go to Step 2 | |
2 |
Does the DTC set? | Go to Step 3 | Go to Diagnostic Aids |
3 |
Important: Following EBCM replacement, use the scan tool to perform the Tire Size Calibration procedure and the Trim Level Calibration procedure, if applicable. Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Did you complete the replacement? | Go to Step 4 | -- |
4 |
Does the DTC reset? | Go to Step 3 | System OK |
As the front wheels spin, each wheel speed sensor produces an AC signal. The electronic brake control module (EBCM) uses the frequency of the AC signals to calculate each wheel speed. The powertrain control module (PCM) converts the signal from the vehicle speed sensor (VSS) to a 128k pulses/mile signal. The EBCM uses the vehicle speed signal from the PCM to calculate the rear wheel speed.
• | The ignition is ON. |
• | The vehicle speed is greater than 8 km/h (4 mph). |
• | No brake application or deceleration is detected. |
• | No wheel slip is detected. |
• | No turning maneuvers are detected. |
• | At least one wheel speed sensor signal is 15% less than or greater than other wheel speed sensor signals. |
• | All of the Conditions for Running and Setting the DTC are present for a cumulative time of 3 minutes during a single ignition cycle. |
• | The EBCM disables the ABS and DRP. |
• | The ABS indicator turns ON. |
• | The brake warning indicator turns ON. |
The Conditions for Setting the DTC are no longer present and you use the scan tool Clear DTCs function.
Installing one tire of significantly different size on the vehicle causes this DTC to set. Operating the vehicle with a tire that has very low air pressure may also set this DTC. Inspect the vehicle for an incorrect or damaged wheel speed sensor or vehicle speed sensor if the tires and the EBCM and PCM calibrations are OK.
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 | |
2 | Inspect both of the front tires on the vehicle to ensure that both tires are of equal size. Are both of the front tires of equal size? | Go to Step 3 | Go to Diagnostic Aids |
3 | Inspect both of the rear tires on the vehicle to ensure that both tires are of equal size. Are both of the rear tires of equal size? | Go to Step 4 | Go to Diagnostic Aids |
Verify the EBCM and the PCM both have the correct tire size calibration. Use the scan tool in order to view the EBCM tire size calibration or perform the Tire Size Calibration procedure and refer to Service Programming System (SPS) in Programming. Did you find and correct the condition? | Go to Step 5 | Go to Diagnostic Aids | |
5 |
Does the DTC reset? | Go to Step 2 | System OK |