GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 2001 🢒 Intrigue 🢒 Brakes 🢒 Antilock Brake System 🢒 DTC U1650

Circuit Description

The Controller Area Network (CAN) serial data circuit is a high speed serial data bus used to communicate information between the steering angle sensor and the EBCM. When the ignition switch is turned to the ON position, the module and the steering angle sensor begin to transmit data between each other.

The CAN bus circuit is monitored continuously after the ignition switch is turned to the ON position.

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

Line interruptions are detected by CAN message monitor.

Action Taken When the DTC Sets

If equiped, the following actions occur:

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

    • CAN HI and CAN LO circuits shorted together.
    • CAN HI or CAN LO circuit shorted to ground.
    • CAN HI or CAN LO circuit shorted to voltage.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. Tests for a short to ground between the CAN HI and CAN LO circuits.

    2.

  2. Tests the CAN HI and CAN LO circuits for a short together.

    3.

  3. Checks to see if steering angle sensor is centered.

Step

Action

Yes

No

Schematic Reference: Antilock Brake System Schematics

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 EBCM.
  3. Install the J 39700 universal pinout box with the J 39700-530 cable adapter to the EBCM harness connector only.
  4. Disconnect the steering angle sensor.
  5. Using the DMM, test the CAN HI and CAN LO circuits for a short to ground between the steering angle sensor and the EBCM. Refer to Testing for Short to Ground in Wiring Systems.

Did you find and correct the condition?

Go to Step 8

Go to Step 3

3

Using the DMM, test the CAN HI and CAN LO circuits between the steering angle sensor and the EBCM for being shorted together. Refer to Circuit Testing in Wiring Systems.

Did you find and correct the condition?

Go to Step 8

Go to Step 4

4

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

Did you successfully complete the centering procedure?

Go to Step 5

Go to Step 6

5
  1. Use the scan tool in order to clear the DTCs.
  2. Test drive the vehicle. Refer to Diagnostic Test Drive .

Did DTC C1650 reset?

Go to Step 7

Go to Step 8

6

Replace the steering angle sensor. Refer to Steering Shaft, Lower Bearing, and Jacket - Disassemble - Off Vehicle in Steering Wheel and Column - Tilt.

Did you complete the replacement?

Go to Step 8

--

7

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

Did you complete the replacement?

Go to Step 8

--

8
  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