DTC B1009 EEPROM Checksum Error. Buick GL7 (Export) 2000

For 1990-2009 cars

### Circuit Description

The EEPROM check sum 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". The only requirements are voltage and ground. This program runs even if the voltage is out of the valid operating range.

### Conditions for Setting the DTC

The microprocessor retains an inverse copy of the digital value stored in certain blocks of memory in the EEPROM. The microprocessor then reads the information from those certain blocks and adds the stored inverse value to the current value. If they do not equal 0, the microprocessor sets this DTC.

### Action Taken When the DTC Sets

The microprocessor reverts to base operation values programed for those blocks of data that have failed the check sum test. The blocks of data that have not failed the check sum test are not affected.

### Conditions for Clearing the MIL/DTC

The DTC clears when the microprocessor runs a successful check sum test of the EEPROM.

### 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