GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 HUMMER 🢒 2007 🢒 H3 🢒 Brakes 🢒 Park Brake 🢒 DTC U1651

Diagnostic Instructions
    • 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.

DTC Descriptor

DTC U1651: Chassis System Dedicated Bus Sensor 1 Malfunction

Circuit/System Description

The yaw rate, lateral and longitudinal accelerometers are combined into one combination sensor external to the electronic brake control module (EBCM). The combination sensor receives ignition power and a ground that is separate from the EBCM. The combination sensor sends dedicated serial data messages to the EBCM regarding vehicle yaw rate, lateral and longitudinal acceleration.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC
    • Ignition voltage to the yaw/lateral combination sensor is less than 9.5 volts.
    • Communication is lost between the EBCM and the combination sensor.

Action Taken When the DTC Sets
    • The EBCM disables the Antilock Brake System (ABS)/Traction Control System (TCS)/Vehicle Stability Enhancement System (VSES) for the duration of the ignition cycle.
    • The ABS indicator turns ON.
    • The driver information center (DIC) displays the ABS FAULT message.
    • The Stability Caution indicator turns on.
    • The DIC displays the SERVICE STAB SYS message.
    • The DIC displays the TRACTION FAILED message.

Conditions for Clearing the DTC
    • The condition for the DTC is no longer present and the DTC is cleared with a scan tool.
    • The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Reference Information

Schematic Reference

Antilock Brake System Schematics

Connector End View Reference

Antilock Brake System Connector End Views

Description and Operation

ABS Description and Operation

Electrical Information Reference

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

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Verification

Verify that the following DTCs are not set: C0186 or C0196.

⇒If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.

Circuit/System Testing
  1. Ignition OFF, disconnect the harness connector at the yaw rate/lateral and longitudinal accelerometer sensor.
  2. Test for less than 1 ohm of resistance between the ground circuit terminal 4 and ground.
    3. ⇒If greater than the specified range, test for an open/high resistance in the ground circuit.
  3. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 1 and ground.
    4. ⇒ If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
  4. Ignition OFF, disconnect the C2 harness connector at the EBCM.
  5. Ignition ON, test for 0 volts between the CAN HI circuit terminal 11 and ground.
    6. ⇒If greater than the specified value, test the CAN HI circuit for a short to voltage.
  6. Test for 0 volts between the CAN LO circuit terminal 25 and ground.
    7. ⇒If greater than the specified value, test the CAN LO circuit for a short to voltage.
  7. Ignition OFF, test for infinite resistance between the CAN HI circuit terminal 11 and ground.
    8. ⇒If not the specified value, test the suspect circuit for a short to ground.
  8. Test for infinite resistance between the CAN LO circuit terminal 25 and ground.
    9. ⇒If not the specified value, test the CAN LO circuit for a short to ground.
  9. Test for less than 1 ohm of resistance between the CAN HI circuit terminal 11 and terminal 2.
    10. ⇒If greater than the specified range, test the CAN HI circuit for an open/high resistance.
  10. Test for less than 1 ohm of resistance between the CAN LO circuit terminal 3 and terminal 25.
    11. ⇒If greater than the specified range, test the CAN LO circuit for an open/high resistance.
  11. Test for infinite resistance between the CAN HI terminal 11 and the CAN LO terminal 25.
    12. ⇒If not the specified value, test the CAN HI and CAN LO circuits for a short together.
  12. If all circuits test normal, replace the Yaw Rate/Lateral sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Vehicle Yaw Sensor with Vehicle Lateral and Longitudinal Accelerometer Replacement