U2099

DTC U2099

DTC DESCRIPTOR

DTC U2099 00
High Speed Communication Enable Circuit

DIAGNOSTIC FAULT INFORMATION




Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection

HS Comm. Cmd.:

TYPICAL SCAN TOOL DATA

CIRCUIT/SYSTEM DESCRIPTION
The body control module (BCM) activates the high speed communication enable circuit, when the ignition key is in ACC, ON or START. The high speed communication enable circuit wakes up the electronic brake control module (EBCM) for bus communication.

CONDITIONS FOR RUNNING THE DTC
The system voltage is between 9-16 volts.

CONDITIONS FOR SETTING THE DTC
The BCM senses a short to voltage on the high speed communication enable circuit.

ACTION TAKEN WHEN THE DTC SETS
The output command is turned off while the malfunction is present.

The modules use a default value for the missing parameters.

CONDITIONS FOR CLEARING THE DTC
- A current DTC clears when the malfunction is no longer present.
- A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction.

DIAGNOSTIC AIDS
Use the DMM MIN/MAX function to capture/locate intermittent conditions.

CIRCUIT/SYSTEM VERIFICATION
Use the scan tool to observe the HS Comm. Cmd. parameter in the BCM data list/outputs with the driver door open and key out of the ignition, and with the ignition in the RUN position. The reading should match the normal range of the typical scan tool data above.

If all parameters are all correct and the DTC is current, replace the BCM.

CIRCUIT/SYSTEM TESTING
1. With the ignition OFF, disconnect the harness connector at the EBCM.
2. Retest for current DTCs. DTC U2099 should remain current.
- If the DTC becomes history, replace the EBCM.
3. Ignition OFF, disconnect the harness connector at the BCM.
4. Test for infinite resistance between the high speed communication enable circuit and ground.
- If less than infinite resistance, repair the enable circuit for a short to ground.
5. If all tests normal, replace the BCM.

REPAIR INSTRUCTIONS
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

Refer to Control Module References for module replacement, setup, and programming. Programming and Relearning