For 1990-2009 cars

### Circuit Description

The non volatile memory check sum write error detection in handled inside the control module. No external circuits are involved.

### Conditions for Running the DTC

The microprocessor runs the program to detect a check sum error after each power up. This program runs only if the DTC B1327 is not set as a current DTCs.

### Conditions for Setting the DTC

The microprocessor sets this DTC if it can not write to non volatile memory. The DTC is also set if the microprocessor can not run an accurate check sum on the non volatile memory.

### Action Taken When the DTC Sets

The theft deterrent control module will store a code B2734 and the SECURITY indicator will be illuminated on steady.

### Conditions for Clearing the MIL/DTC

The DTC clears when the microprocessor runs either a successful check sum test or a successful write to the non-volatile memory.

### 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 received as a current DTC, do not replace the module.

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

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. Ensure that a learned master ignition key is being used when performing the Vehicle Theft Deterrent Diagnostic System Check.

2. The theft deterrent control module must be programmed to the vehicle.

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Theft Deterrent System Schematics Connector End View Reference: Theft Deterrent System Connector End Views
1 | Did you perform the Theft Deterrent Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Theft Deterrent
2 |

1. Install a scan tool.
2. Turn ignition switch ON.
3. Retrieve DTCs.

Is DTC retrieved as a current DTC?

Go to Step 3

Go to Diagnostic Aids

3 | Important: If a 10 Minute or 30 Minute Re-Learn Procedure is performed, all keys not learned at that time will be erased and will not be recognized. Perform the Adding Keys procedure on all keys or instruct the customer how to perform the Adding Keys procedure. Refer to Adding Keys .

1. Replace the theft deterrent control module . Refer to Theft Deterrent Module Replacement .
2. With a scan tool, perform the Set Up New VTD Module procedure in the Vehicle Theft Deterrent, Special Functions data list.
3. Perform the programming theft deterrent system components procedure. Refer to Programming Theft Deterrent System Components .

Did you complete the replacement?

Go to Step 4

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4 |

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK