U2105

DTC U2105-U2199

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC U2142 00

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Lost Communication With Yaw Rate Sensor (YRS)

Circuit/System Description

Modules connected to the CAN bus serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. The modules have prerecorded information about what messages are needed to be exchanged on the serial data circuits. The messages are supervised and also, some periodic messages are used by the receiver module as an availability indication of the transmitter module. Each message contains the identification number of the transmitter module.

The electronic brake control module (EBCM) activates the other modules connected to the CAN serial data circuits by applying voltage when the ignition key is in ACC, ON or START. The EBCM and the yaw and lateral accelerometer sensor are the only modules connected to the CAN bus serial data circuits.

Conditions for Running the DTC

* The system voltage is between 9-16 volts.

* The vehicle power mode master requires serial data communication to occur.

Conditions for Setting the DTC

A supervised periodic message that includes the transmitter module availability has not been received.

Action Taken When the DTC Sets

* The vehicle stability enhancement system (VSES), if equipped, and traction control system (TCS) will not function.

* System OFF lamps will illuminate for these systems.

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.

Reference Information

Schematic Reference

* Data Communication Schematics Electrical Diagrams

* Control Module References Control Module References

Connector End View Reference

Component Connector End Views 1-2 Shift Solenoid (SS) Valve (M30)

Description and Operation

Data Link Communications Description and Operation Description and Operation

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the yaw and lateral accelerometer sensor.

2. Ignition OFF, test for less than 10 ohms between the sensor ground circuit terminal and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify that a test lamp illuminates between the sensor ignition circuit terminal and ground.

• If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the EBCM.

4. Ignition OFF, disconnect the harness connector at the EBCM

5. Test for less than 1 ohms in each serial data circuit between the yaw and lateral accelerometer sensor and the EBCM.

• If greater than the specified value, test the yaw and lateral accelerometer sensor serial data circuits for an open/high resistance.

6. If all circuits test normal, replace the yaw and lateral accelerometer sensor.

Repair Instructions

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

* GMLAN Wiring Repairs GMLAN Wiring Repairs

* Vehicle Yaw Sensor with Vehicle Lateral and Longitudinal Accelerometer Replacement

* Vehicle Yaw Sensor with Vehicle Lateral Accelerometer Replacement Non-Hybrid Greater than/Equal to 3900 kg (8600 lb) GVW

* Vehicle Yaw Sensor with Vehicle Lateral Accelerometer Replacement Non-Hybrid Greater than/Equal to 3900 kg (8600 lb) GVW

* Control Module References Control Module References for module replacement, setup, and programming.