Test Description

WARNING: This page is about a different car, the 2004 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

2: Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
5: The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.

Diagnostic System Check - Automatic Transmission Shift Lock Control

Step	Action	Yes	No
1	Install a scan tool. Does the scan tool power up?	Go to Step 2	Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications
2	Turn ON the ignition, with the engine OFF. Attempt to establish communication with the Dash Integration Module (DIM), Powertrain Control Module (PCM), and the Rear Integration Module (RIM). Does the scan tool communicate with the DIM, the PCM, and the RIM?	Go to Step 3	Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications
3	IMPORTANT: The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode. Access the Ignition Switch parameter in the body control module (BCM) inputs data display list. Rotate the ignition switch through all positions while observing the ignition switch power mode parameter. Does the ignition switch parameter reading match the ignition switch position for all switch positions?	Go to Step 4	Go to Power Mode Mismatch in Body Control System
4	Select the display DTCs function on the scan tool for the DIM, the PCM, and the RIM. Does the scan tool display any DTCs for the DIM, the PCM, or the RIM?	Go to Step 5	Go to Symptoms - Automatic Transmission Shift Lock Control
5	Does the scan tool display any DTCs which begin with a "U"?	Go to Diagnostic Trouble Code (DTC) List in Data Link Communications	Go to Step 6
6	Does the scan tool display DTC B1000, B1004, B1007, or B1009?	Go to Diagnostic Trouble Code (DTC) List in Body Control System	Go to Step 7
7	Does the scan tool display DTC B1327?	Go to Diagnostic Trouble Code (DTC) List in Engine Electrical	Go to Symptoms - Automatic Transmission Shift Lock Control