Test Description

WARNING: This page is about a different car, the 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, 2002 Chevrolet Silverado, and 2002 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) - A partial loss of communication in the class 2 serial data circuit uses a different procedure than a total loss of communication of the class 2 serial data circuit.
4) - The following DTCs may be retrieved with a history status. The DTCs are not the cause of the present condition.
- U1300
- U1301
- U1305
6) - A State of Health DTC with a history status may be present along with a U1000 or U1255 with a current status. This indicates that the malfunction occurred when the ignition was on.
10) - Normal class 2 serial data communication cannot take place until the body control module (BCM) sends the appropriate power mode message. If the BCM does not send a wake-up message, other modules on the class 2 serial data circuit may not communicate.
12) - Normal class 2 serial data communication cannot take place until the body control module (BCM) sends the appropriate power mode message. If the BCM does not send a wake-up message, other modules on the class 2 serial data circuit may not communication.
17) - If there are no current DTCs that begin with the letter "U", the communication concern has been repaired.
18) - The communication concern may have prevented diagnostic of the customer complaint.

Fig 1: Scan Tool Does Not Communicate With Class 2 Device Diagnosis (Steps 1-9)

Courtesy of GENERAL MOTORS CORP.

Fig 2: Scan Tool Does Not Communicate With Class 2 Device Diagnosis (Steps 10-15)

Courtesy of GENERAL MOTORS CORP.

Fig 3: Scan Tool Does Not Communicate With Class 2 Device Diagnosis (Steps 16-20)

Courtesy of GENERAL MOTORS CORP.