Jeep Compass 2007-2009
Jeep Patriot 2007-2009
Diagnosis of base brake conditions which are mechanical in nature should be performed first. This includes brake noise, lack of power assist, parking brake, or vehicle vibration during normal braking. The Anti-lock brake system performs several self-tests every time the ignition switch is turned ON and the vehicle is driven. The Anti-Lock Brake Module (ABM) monitors the system inputs and outputs circuits to verify the system is operating properly. If the ABM senses a malfunction in the system it will set a DTC into memory and trigger the warning lamp.
If the conditions that set the DTC are not present, the following list may help in identifying an intermittent condition:
- Refer to any Technical Service Bulletins (TSB-s) that may apply.
- Review the scan tool Environmental Data information. If possible, try to duplicate the conditions under which the DTC was set.
- Turn the ignition OFF .
- Visually inspect the related wire harness. Disconnect all the related harness connectors. Look for any chafed, pierced, pinched, partially broken wires, and/or broken, bent, pushed out, or corroded terminals.
- Perform a voltage drop test on the related circuits between the suspected faulty component and the Anti-Lock Brake Module.
- Inspect and clean all PCM, ABS, engine, and chassis grounds that are related to the most current DTC.
- If numerous trouble codes were set, look for any common ground or supply circuit using a wire schematic.
- For any Relay DTC-s, actuate the Relay with the scan tool and wiggle the related wire harness to try to interrupt the actuation.
- Use the scan tool to perform a System Test if one applies to the failing component.
A co-pilot, data recorder, and/or lab scope should be used to help diagnose intermittent conditions.
CAUTIONEnsure braking capability is available before road testing.
- With the ignition OFF , connect all previously disconnected components and connectors.
- Ensure all accessories are turned off and the battery is fully charged.
- With the ignition ON and the engine OFF, erase all DTC-s from all modules using a scan tool.
- Start the engine and allow it to run for 2 minutes and fully operate the system that was malfunctioning.
- Turn the ignition OFF and wait 5 seconds. Turn the ignition ON and check for any DTC-s using the scan tool.
- If any DTC-s are present, return to the vehicle DTC list and perform the appropriate diagnostic procedure.
- If there are no DTC-s present after turning ignition ON , road test the vehicle for at least 5 minutes. Perform several anti-lock braking stops.
- Again, with the scan tool, check for DTC-s. If any DTC-s are present, refer to the Table of Contents in the applicable Section for the diagnostic test procedure and perform the appropriate diagnostic procedure.
- If there are no DTC-s present, and the problem can no longer be duplicated, the repair is complete.