• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

For symptom byte information, refer to Symptom Byte List.

The internal fault detection is handled inside the device. The symptom byte information is for engineering reference only. No external circuit diagnosis is involved.

• The device runs the program to detect an internal fault when power up is commanded. The only requirements are voltage and ground. This program runs even if the voltage is out of the valid operating range.
• The keyless entry control module will set this DTC with symptom byte 39 when the keyless entry control module antenna is activated.

The device has detected an internal malfunction.

The device refuses all additional inputs.

• A current DTC clears when the malfunction is no longer present.
• A history DTC clears when the device ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.

• This DTC may be stored as a history DTC without affecting the operation of the device.
• Do not replace a device based only on DTC B101D being set in history with the exception of the following devices:
• K36 Inflatable Restraint Sensing and Diagnostic Module (SDM)
• K85 Passenger Presence Module
• If DTC B101D is set as current, replace the appropriate device.

• Data Communication Schematics
• Control Module References

Master Electrical Component List

Data Link Communications Description and Operation

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Control Module References for scan tool information

1. Ignition ON/Vehicle In Service Mode.
2. Verify DTC B101D is not set as current.
• If DTC B101D is set as current

  Replace the device that sets the DTC.

• If DTC B101D is not set as current or is set as history
3. All OK

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for device replacement, programming and setup