Body Control System Diagnosis

DTC B1009 EEPROM Checksum Error

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

If this DTC is retrieved as either a current or a history DTC, replace the module.