For 1990-2009 cars

### Circuit Description

The internal fault detection is handled inside the control module. No external circuits are involved.

### Conditions for Running the DTC

The control module runs a program to detect any internal errors when power up is commanded. The only requirements are voltage and ground.

### Conditions for Setting the DTC

The control module detects an internal module malfunction.

### Action Taken When the DTC Sets

The microprocessor will not function properly. All Vehicle Theft Deterrent functions will be inoperative.

### Conditions for Clearing the DTC

• | The current DTC 055 will clear when the microprocessor makes a successful internal integity check after changing power modes from RUN to OFF and back to RUN.

• | A history DTC 055 will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.

### Diagnostic Aids

• | This DTC may be stored as a history DTC with out affecting the operation of the module. If stored only as a history DTC and not retrieved as a current DTC, do not replace the module.

• | If this DTC is retrieved as both a Current and History DTC, replace the module.

Step | Action | Yes | No
--- | --- | --- | ---
1 | Perform the appropriate Diagnostic System Check. Refer to Diagnostic System Check - Theft Deterrent . Did you perform the control module diagnostic system check? | Go to Step 2 | Go to Diagnostic System Check - Theft Deterrent
2 | Is the DTC retrieved as a current and history DTC? | Go to Step 3 | Go to Diagnostic Aids
3 | Important: Perform the set up procedure for the control module if needed. Replace the control module. Refer to Theft Deterrent Module Replacement . Did you complete the replacement? | System OK | --