Test Description
WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 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.
- 1: This step determines if the scan tool is receiving power through the DLC connector.
- 2: The MIL should illuminate whenever the ignition is ON and the engine is not running.
- 3: This step determines if the TCM is transmitting Class 2 serial data to the DLC and that the Class 2 data circuit is not open or shorted.
- 4: This step determines if a DTC is current or stored in history.
Diagnostic System Check - Automatic Transmission
| Step | Action | Yes | No |
|---|---|---|---|
| 1 |
IMPORTANT:
Check for applicable service bulletins before proceeding with this test. Perform this test only if there is a driveability concern or if you have been directed to this table from another section in the service information.
IMPORTANT:
Do not turn the ignition OFF when performing this diagnostic procedure. Do not clear the DTCs unless instructed by this diagnostic procedure.
|
Go to Step 2 | Go to Scan Tool Does Not Power Up in Data Link Communication |
| 2 | Is the MIL ON? | Go to Step 3 | Go to Symptoms - Instrument Panel, Gages and Console in Instrument Panel, Gages, and Console |
| 3 | Attempt to establish communication with the TCM. Does the scan tool communicate with the TCM? |
Go to Step 4 | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communication |
| 4 |
IMPORTANT:
DTCs, engine performance, and transmission default actions can greatly affect the transmission performance. Ensure that these items are not the cause of a transmission concern. Use the scan tool Capture Info function in order to save or capture, Store Info, any DTC Information.Are there any DTCs present? |
Go to Diagnostic Trouble Code (DTC) List/Type | Go to Symptoms - Automatic Transmission |