Test Description

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

2: Lack of communication may be due to partial or total malfunction of the serial data circuit. The specified procedure will determine the particular condition.
4: The presence of DTCs that begin with a "U" indicates that some other module is not communicating. The specified procedure will compile all of the available information before tests are performed.
5: Since the VSES interacts extensively with powertrain control systems, powertrain related DTCs should be diagnosed and repaired prior to diagnosing any VSES concerns.
6: The presence of this DTC, which the scan tool may display in Powertrain, may cause the EBCM to set DTC C0283.
7: The presence of this DTC, which may be set by the body control module (BCM), may cause the EBCM to set DTC C0455.

Diagnostic System Check - ABS (W/JL4)

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 the ignition ON. Use the scan tool Class 2 Message Monitor feature to verify communication with the following control modules. EBCM PCM IPC BCM ATC (W/NR4) Does the scan tool communicate with all of the control modules listed above?	Go to Step 3	Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications
3	Use the scan tool to display DTCs for the following systems or specific control modules. VSES Powertrain Instrument Panel Cluster Body Control Module Does the scan tool display any DTCs for the control modules listed above?	Go to Step 4	Go to Symptoms - Antilock Brake System
4	Does the scan tool display any DTCs that begin with a "U"?	Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications	Go to Step 5
5	Does the scan tool display any DTCs that begin with a "P"?	Go to Diagnostic System Check - Engine Controls in Engine Controls - 4.8L, 5.3L, or 6.0L	Go to Step 6
6	Does the scan tool display DTC B2725?	Go to Diagnostic System Check - Transfer Case in Transfer Case - BW 4482-NR4	Go to Step 7
7	Does the scan tool display DTC B2620?	Go to Diagnostic System Check - Lighting Systems in Lighting Systems	Go to Diagnostic Trouble Code (DTC) List