GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

1

Retrieve and display DTCs by entering the BCM diagnostic mode. Refer to On-Board Diagnostic Features .

Did you enter Diagnostic Mode and retrieve DTCs from the body control module?

Go to Step 2

Go to Cannot Enter BCM Diagnostics

2

Did you retrieve both DTCs 12 and 55?

Go to Step 3

Go to Cannot Enter BCM Diagnostics

3

Did you retrieve both DTCs 25 and 35?

Go to Step 5

Go to Step 4

4

Did you retrieve DTC 35 with no DTC 25?

Go to Diagnostic Trouble Code (DTC) List in Theft Deterrent

Go to Step 5

5

Did you retrieve any DTCs other than 12, 25/35, 55 and configuration ID numbers?

Go to Diagnostic Trouble Code (DTC) List

Go to the Diagnostic System Check of the system exhibiting symptoms. Refer to Control Module References