Diagnostic Aids

WARNING: This page is about a different car, the 2008 GMC Sierra, 2008 GMC Cab & Chassis Sierra, 2008 Chevrolet Silverado, and 2008 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Inspect the wiring for poor electrical connections at the TCM. Inspect for the following conditions:
- A bent terminal
- A backed-out terminal
- A damaged terminal
- Poor terminal tension
- A chafed wire
- A broken wire inside the insulation
When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.
You may have to drive the vehicle in order to experience a condition.
Inspect for the presence of aftermarket accessories, such as a remote starter, etc. Depending on how these aftermarket accessories are installed, they may interfere with the required voltage for proper operation of the transmission.

Step	Action	Value	Yes	No
Schematic Reference: Automatic Transmission Controls Schematics
1	Did you perform the Diagnostic System Check - Vehicle?	-	Go to Step 2	Go to Diagnostic System Check - Vehicle
2	Install the scan tool. Turn ON the ignition, with the engine OFF. IMPORTANT: Before clearing the DTC, use the scan tool in order to record the Freeze Frame and Failure Records for reference. The Clear Info function will erase the data. Record the DTC Freeze Frame and Failure Records. Clear the DTC. Using the DMM, measure and record voltage at the battery terminals. Is voltage within the specified value?	B+	Go to Step 3	Go to Step 4
3	Start the engine and observe the charge indicator on the instrument cluster. Refer to Charging System Test . Does the charge indicator display voltage higher than specified value?	18 V	Go to Step 5	Go to Step 6
4	Replace the battery, or resolve the battery condition. Refer to Battery Inspection/Test . Did you resolve the condition or complete the replacement?	-	Go to Step 6	-
5	Repair the charging system. Refer to Charging System Test or Generator Replacement (4.3L) or Generator Replacement (4.8L, 5.3L, 6.0L, and 6.2L) or Generator Replacement (6.6L) . Did you complete the repair?	-	Go to Step 6	-
6	Perform the following procedure in order to verify the repair: Clear the DTC. Using the scan tool, monitor TCM voltage. Select Specific DTC. Enter DTC P0563. Has the test run and passed?	-	Go to Step 7	Go to Step 2
7	With the scan tool, observe the stored information, capture info, and DTC Info. Does the scan tool display any DTCs that you have not diagnosed?	-	Go to Diagnostic Trouble Code (DTC) List - Vehicle	System OK