Automatic Transmission Warning Lamp Flashes Continuously. Chevrolet Joy 2008

For 1990-2009 cars

### Circuit Description

The fuse supplies battery voltage at all times to the A/T warning lamp that is connected to the transmission control module (TCM) connector terminal 17. The TCM will illuminate the A/T warning lamp for approximately 3 seconds, while performing diagnostic tests on the transmission system. The Fuse supplies battery voltage to the TCM at terminals 10 and 11, when the ignition switch is in the ON or START positions.

### Test Description

The number below refers to the step number on the diagnostic table.

1. This test checks for a short.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Was the Diagnostic System Check - Automatic Transmission performed? | -- | Go to Step 2 | Go to Diagnostic System Check - Automatic Transmission

2

1. Turn the ignition switch to the LOCK position.
2. Disconnect the transmission control module (TCM).
3. Measure the resistance between the TCM harness connector terminal 17 and ground.

Is the resistance measured less than the specified value?

OL ∞

Go to Step 3

Go to Step 4

3 | Repair the short to ground in the instrument panel (I/P) wiring harness between the data link connector (DLC) and the sensing and diagnostic module (SDM). Are all the repairs complete? | -- | System OK | --
4 | Replace the TCM. Did you complete the replacement? | -- | System OK | --