Wireless Control Module (WCM) Pre-Diagnostic Procedure

WIRELESS CONTROL MODULE (WCM) PRE-DIAGNOSTIC PROCEDURE

Before attempting to repair any theft or security system, technicians should be familiar with and fully understand the system operation. Vehicle Theft Security System - Description. The following should be used as a checklist to be completed in its entirety prior to referencing specific Theft and Security Diagnostic Procedures.

FOLLOW THE BASIC OUTLINE IN THE SIX-STEP TROUBLESHOOTING PROCEDURE

- Verification of complaint
- Verification of any related symptoms
- Symptom analysis
- Problem isolation
- Repair of isolated problem
- Verification of proper operation

TAKE INTO ACCOUNT CURRENT VEHICLE CONDITION, REPAIR HISTORY, AND TECHNICAL SERVICE BULLETINS (TSBs)

- Verify there are no outward signs of vehicle damage that could impact the proper operation of the theft or security system. Check for aftermarket vehicle accessories that may have been installed improperly or could interfere with the system
- Check the vehicle repair history for repairs that may relate to the current condition.
- Perform a check of current Technical Service Bulletins (TSB) for the system related to the customer concern. If a TSB applies, follow the procedure outlined in the TSB.

DIAGNOSE ONLY THOSE FAILURES THAT ARE ACTIVE AND CAN BE REPRODUCED

- Check the control module central to the subsystem that is exhibiting the condition for active Diagnostic Trouble Codes (DTCs).
- For an intermittent failure that is not current at the time of vehicle inspection, refer to the WIRELESS CONTROL MODULE INTERMITTENT TEST Wireless Control Module (WCM) Intermittent Condition Test and document the event on the repair order.

ADDRESS ACTIVE DTCS IN THE CORRECT ORDER

- Low/High Voltage and Serial Data Loss of Communication Codes
- Module Internal Failure and Configuration Mismatch Codes
- Circuit specific DTC failures

As a general rule, for any theft/security system control module that exhibits more than one active DTC, address the codes in the order indicated; should the malfunction still be present after conducting this Pre-diagnostic Procedure, technicians should continue to the appropriate DTC procedure or symptom diagnostic.