| • | The system voltage is between 9-18 volts. | 
| • | Road test the vehicle. Refer to Road Test . | 
Malfunction of the lockup clutch.
The transmission control module (TCM) illuminates the A/T warning lamp when the diagnostic runs and fails.
The TCM turns OFF the A/T warning lamp when the diagnostic runs and does not fail.
Step  | Action  | Yes  | No  | 
|---|---|---|---|
1  | Did you perform the Diagnostic System Check?  | Go to Step 2  | |
2  | Are any other DTCs set?  | Go to Diagnostic Trouble Code (DTC) List  | Go to Step 3  | 
3  | Disassemble transmission and repair an internal transmission fault with the lockup clutch or the control valve. Did you complete the repair?  | Go to Step 4  | Go to Step 4  | 
4  | 
 Does the DTC reset?  | Go to Step 2  | System OK  |