Telematics Control Unit
To avoid serious or fatal injury on vehicles equipped with airbags, disable the Supplemental Restraint System (SRS) before attempting any steering wheel, steering column, airbag, seat belt tensioner, impact sensor or instrument panel component diagnosis or service. Disconnect and isolate the battery negative (ground) cable, then wait two minutes for the system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the SRS. Failure to take the proper precautions could result in accidental airbag deployment.
The hard wired circuits between components related to the Telematics Control Unit (TCU) may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin out information and location views for the various wire harness connectors, splices and grounds.
However, conventional diagnostic methods will not prove conclusive in the diagnosis of the TCU or the electronic control and communication features of the TCU. The most reliable, efficient and accurate means to diagnose the TCU or the electronic control and communication features related to TCU operation requires the use of a diagnostic scan tool. Refer to DTC TROUBLESHOOTING .