For 1990-2009 cars

### Circuit Description

The non volatile memory check sum and write error detection is 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 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 VTD module will store a code B2734 and no driver warning message will be displayed.

### 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 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.

### Test Description

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

1. Be sure that the original ignition key issued with the vehicle is used when performing the Vehicle Theft Deterrent Diagnostic System Check.

2. The vehicle theft deterrent (VTD) module must be programmed to the vehicle.

Step | Action | Yes | No
--- | --- | --- | ---
1 | Did you perform A Diagnostic System Check - Vehicle Theft Deterrent? | 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: Perform the vehicle theft deterrent module set up procedure. Replace the vehicle theft deterrent (VTD) module . Refer to PASS-Key III Module Replacement . Did you complete the replacement? | Go to Step 4 | --
4 |

1. Clear the DTCs using the scan tool.
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