LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1417 (Power Sun Roof) >> Diagnostic Information & Procedures >> Diagnostic System Check - Power Sunroof >> Test Description

Test Description

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2002 GMC Yukon XL, 2002 GMC Yukon, 2002 Chevrolet Tahoe, 2002 Chevrolet Suburban, and 2002 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

The number(s) below refer to the step number(s) on the diagnostic table.

  1. 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.
  2. 4:  Determining if any DTCs are set. If no DTCs are set then proceed to the Symptoms.
  3. 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.
  4. 6:  The presence of either of these DTCs will inhibit the operation of the sunroof. If no DTCs are set then proceed to the Symptoms.
Diagnostic System Check - Power Sunroof

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
2 
  1. Turn ON the ignition, with the engine OFF.
  2. Attempt to establish communication with the Body Control Module (BCM).
Does the scan tool communicate with the BCM?		 Go to Step 3  Go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE
3
IMPORTANT: The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode.
  1. Access the Class 2 Power Mode in the Diagnostic Circuit Check on the scan tool.
  2. 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
4  Select the BCM display DTCs function on the scan tool.
Does the scan tool display any DTCs?		 Go to Step 5  Go to Symptoms - Roof 
5  Select the BCM display DTCs function on the scan tool.
Does the scan tool display any DTCs which begin with a "U"?		 Go to DIAGNOSTIC TROUBLE CODE (DTC) LIST Go to Step 6 
6  Does the scan tool display DTC B1477, or B1478? Go to DIAGNOSTIC TROUBLE CODE (DTC) LIST Go to Symptoms - Roof 
scientia non olet · About LEMON Manuals