Diagnostic Test
- CHECK FOR AN ACTIVE DTC NOTE:
This DTC must be active for the results of this test to be valid.
- Turn the ignition on.
- With the scan tool, read ABS DTCs and record on the repair order.
- With the scan tool, read and record Environmental Data to help identify the conditions in which the DTC was set.
- With the scan tool, erase ABS DTCs.
- Start the engine.
- Press the brake pedal firmly and release.
- With the scan tool, read ABS DTCs.
Is the DTC active?
Yes
- Go To 2
No
- Perform the ABS INTERMITTENT CONDITION TEST. Refer to ABS INTERMITTENT CONDITION .
- MECHANICAL BRAKE SYSTEM INSPECTION
- Turn the ignition off.
- Check the brake fluid level.
- Check for base brake issues.
- Check the brake fluid for contaminants.
- Visually inspect the Brake Master Cylinder and all brake line fittings.
- Visually inspect the brake lines between the Brake Master Cylinder and the Integrated Control Unit (ICU) for bent, damaged, or pinched restrictions.
Were any problems found?
Yes
- Repair as necessary.
- Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
No
- Go To 3
- PRIMARY CIRCUIT PRESSURE
- BRAKE PEDAL INSPECTION
- Turn the ignition off.
- Check the brake pedal for damage or restrictions not allowing it to fully return.
Were any problems found?
Yes
- Repair as necessary.
- Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
No
- Go To 6
- BRAKE PEDAL POSITION (BPP) SENSOR
- Start the engine.
- With the scan tool, under "Data Display" monitor the BPP Sensor and the primary circuit pressure.
Did the BPP Sensor indicate pressed without the brake pedal pressed?
Yes
- Replace the Brake Pedal Position (BPP) Sensor in accordance with the Service Information. Refer to SENSOR, STOP LAMP, REMOVAL AND INSTALLATION .
- Perform the ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
No
- Go To 6
- CHECK RELATED HARNESS CONNECTIONS
- Turn the ignition off.
- Disconnect the ABS Module harness connector.
- Disconnect all related in-line harness connections (if equipped).
- Disconnect the related component harness connectors.
- Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
- Proper connector installation.
- Damaged connector locks.
- Corrosion.
- Other signs of water intrusion.
- Weather seal damage (if equipped).
- Bent terminals.
- Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
- Terminals that have been pushed back into the connector cavity.
- Perform a terminal drag test on each connector terminal to verify proper terminal tension.
Repair any conditions that are found.
- Connect the ABS Module harness connector. Be certain that the harness connector is fully seated and the connector lock is fully engaged.
- Connect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
- Connect the related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
- With the scan tool, erase DTCs.WARNING:
To avoid possible serious or fatal injury, check brake capability is available before road testing.
- Using the recorded Event and Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
- With the scan tool, read ABS Module DTCs.
Did the DTC return?
Yes
NOTE:For this failure it is necessary to replace both the Anti-lock Brake System (ABS) Module and the Hydraulic Control Unit (HCU) as a complete unit. This is known as the Integrated Control Unit (ICU).
- Replace the Anti-lock Brake System (ABS) Module in accordance with the Service Information. Refer to MODULE, ANTI-LOCK BRAKE SYSTEM (ABS), REMOVAL AND INSTALLATION .
- Perform ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
No
- Perform ABS VERIFICATION TEST. Refer to ABS VERIFICATION TEST .
- Test complete.