Principles of Operation

The vehicle has one module communication network. The communication network can be connected to the diagnostic tool by a connector called the data link connector (DLC). This makes diagnosis and testing of systems easier by allowing one smart tester to be able to diagnose and test any module on the network. The DLC that is OBDII compliant and provides the diagnostic tool with power and ground can be found under the steering column. The powertrain control module (PCM), anti-lock brake control module, transmission control module (TCM) and the air bag diagnostic monitor are all connected to the communication network.

The anti-lock brake control module controls the brake pressure to the four wheels to keep the vehicle under control while braking. For additional information, refer to ANTI-LOCK CONTROL .

The air bag diagnostic monitor controls the deployment of the air bags based on sensor input. For additional information, refer to AIR BAG RESTRAINT SYSTEMS .

The PCM controls the engine performance, electronic ignition, emission controls and on-board diagnostics. For additional information, refer to the appropriate ENGINE PERFORMANCE article. .

The TCM controls transmission shifting and lock-up events. For additional information, refer to AUTOMATIC TRANSAXLE/TRANSMISSION .