GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2004 🢒 Grand Prix 🢒 Brakes 🢒 Antilock Brake System 🢒 DTC U1651

Circuit Description

The EBCM monitors the received messages from the steering angle sensor for corruption or for missing messages.

Conditions for Running the DTC
    • The ignition is ON.
    • The vehicle speed is greater than 40 km/h (25 mph).

Conditions for Setting the DTC

The EBCM receives a corrupt or a missing message after 100 milliseconds.

Action Taken When the DTC Sets

If equipped, the following actions occur:

    • The EBCM disables theTCS/VSES and for the duration of the ignition cycle.
    • A malfunction DTC will set.
    • The Stability Off indicator turns on.

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

Diagnostic Aids

Possible causes of this DTC are as follows:

    • An open in the CAN HI or CAN LO circuit.
    • An open in the ignition circuit.
    • An open in the ground circuit.
    • Malfunctioning steering angle sensor.
    • Malfunctioning EBCM.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Tests the ignition circuit for an open.

    2.

  2. Checks the ground circuit for an open.

    3.

  3. Tests the CAN HI circuit for an open.

    4.

  4. Tests the CAN LO circuit for an open.

    5.

  5. Checks the steering angle sensor connector for poor connections.

Step

Action

Yes

No

Schematic Reference: Antilock Brake System Schematics

Connector End View Reference: Antilock Brake System Connector End Views

1

Did you perform the ABS Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - ABS

2

  1. Turn OFF the ignition.
  2. Disconnect the steering angle sensor harness connector.
  3. Using a DMM, check the ignition circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 3

3

  1. Disconnect the EBCM harness connector.
  2. Install the J 39700 Universal Pinout Box with the J 39700-530 Cable Adapter between the EBCM and the EBCM harness connector.
  3. Disconnect the steering angle sensor.
  4. Using a DMM, check the ground circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 4

4

Using a DMM, check the CAN HI circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 5

5

Using a DMM, check the CAN LO circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 6

6

Inspect for poor connections at the harness connector of the steering angle sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 7

7

Inspect for poor connections at the harness connector of the EBCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 8

8

Perform the steering angle sensor centering procedure. Refer to Steering Angle Sensor Centering .

Did you successfully complete the centering procedure?

Go to Step 9

Go to Step 10

9
  1. Use the scan tool in order to clear the DTCs.
  2. Test drive the vehicle. Refer to Diagnostic Test Drive .

Did DTC C1651 reset?

Go to Step 11

Go to Step 12

10

Replace the steering angle sensor. Refer to Steering Wheel Position Sensor or Steering Shaft Lower Bearing Replacement in Steering Wheel and Column.

Did you complete the replacement?

Go to Step 12

--

11

Replace the EBCM. Refer to Electronic Brake Control Module Replacement .

Did you complete the replacement?

Go to Step 12

--

12
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting test.

Does the DTC reset?

Go to Step 2

System OK