Diagnostic Test
- VERIFY THE DTC IS ACTIVE NOTE:
This DTC must be active for the results of this test to be valid.
- Turn the ignition on.
- With the scan tool, read and record DTCs.
- With the scan tool, read and record Freeze Fame information.
- With the scan tool, erase DTCs.
- Start the engine.
- Press the brake pedal firmly and release.
- With the scan tool, read and record DTCs.
Is the DTC active at this time?
Yes
- Go To 2.
No
- Perform the ABS INTERMITTENT CONDITION TEST. Refer to ABS INTERMITTENT CONDITION .
- CHECK BRAKE PRESSURE SENSOR
- Start the engine.
- With the scan tool look at Brake Pressure Sensor Signal and the Brake Switch Signal.
- With the brakes not applied the Pressure Sensor should read ±15 bar (218 psi).
- Apply the brakes the Pressure Sensor should read above 15 bar (218 psi).
Did Brake Pressure Sensor increase above 15 bar (218 psi)?
Yes
- Replace the Antilock Brake System (ABS) Module in accordance with the Service Information. Refer to MODULE, ANTI-LOCK BRAKE SYSTEM, REMOVAL .
- Replace the Hydraulic Control Unit (HCU) in accordance with the Service Information. Refer to HYDRAULIC CONTROL UNIT (HCU), REMOVAL .
- Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
NOTE:For this failure it is necessary to replace both the ABS Module and the HCU as a complete unit.
No
- Go To 3.
- CHECK FOR AIR IN BRAKE SYSTEM NOTE:
Before continuing the brake system must be bled to verify there is no air in the brake system.
- Turn ignition off.
- Bleed brake system.
Was there any air in the brake system?
Yes
- Repair as needed.
- Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
No
- Replace the Antilock Brake System (ABS) Module in accordance with the Service Information. Refer to MODULE, ANTI-LOCK BRAKE SYSTEM, REMOVAL .
- Replace the Hydraulic Control Unit (HCU) in accordance with the Service Information. Refer to HYDRAULIC CONTROL UNIT (HCU), REMOVAL .
- Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
NOTE:For this failure it is necessary to replace both the ABS Module and the HCU as a complete unit.