Test Description

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. 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: The lack of communication may be caused by a partial or a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
4: If no DTCs are present refer to the symptom list in Symptoms in order to determine the correct diagnostic procedure to use.
5: The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will collect all the available information before tests are performed.

Diagnostic System Check - Power Seat Systems

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 Power Up in Data Link Communications
2	Turn ON the ignition, with the engine OFF. Attempt to establish communication with the following control modules: Powertrain control module Body control module Driver door module Passenger door module Driver seat module Does the scan tool communicate with the listed control modules?	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 Class 2 Power Mode in the Diagnostic Circuit Check on the scan tool. Rotate the ignition switch through all of the positions while observing the ignition switch power mode parameter. Do the ignition switch power mode parameter readings match the actual ignition 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 following control modules: Powertrain control module Body control module Driver door module Passenger door module Driver seat module Does the scan tool display any DTCs?	Go to Step 5	Go to Symptoms - Seats
5	Does the scan tool display any DTC that begins with a "U"?	Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications	Go to Step 6
6	Does the scan tool display B1000?	Go to Diagnostic Trouble Code (DTC) List in Body Control System	Go to Step 7
7	Does the scan tool display DTC P0562 or P0563?	Go to Diagnostic Trouble Code (DTC) List in Engine Electrical	Go to Diagnostic Trouble Code (DTC) List