GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The electronic brake control module (EBCM) monitors the deceleration of the vehicle for Antilock Brake System (ABS) operation.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C1381 Yaw Rate Circuit Malfunction

Conditions for Running the DTC

DTC C1381 can be set anytime the vehicle speed is above 3 km/h (2 mph).

Conditions for Setting the DTC

The EBCM detects malfunction in the deceleration sensor.

Action Taken When the DTC Sets

    • The ABS is disabled.
    • The ABS warning indicator turns ON.
    • The traction control and vehicle stability control (VSC) is disabled.
    • The VSC warning indicator turns ON.

Conditions for Clearing the DTC

The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.

Diagnostic Aids

Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction.

The following are possible causes of the malfunction:

    • An open or high resistance in the deceleration voltage circuit
    • An open or high resistance in the deceleration sensor ground circuit
    • A deceleration sensor malfunction

If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections .

Test Description

The number below refers to the step number on the diagnostic table.

  1. Test the deceleration sensor ground circuit for a high resistance or an open.

Step

Action

Value(s)

Yes

No

Schematic Reference: Antilock Brake System Schematics

Connector End View Reference: Antilock Brake System Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Is U0073, U0123, U0124, or U0126 also set?

--

Go to Diagnostic Trouble Code (DTC) List - Vehicle

Go to Step 3

3

  1. Disconnect the deceleration sensor connector.
  2. Turn ON the ignition, with the engine OFF.
  3. Measure the voltage of the deceleration sensor ignition positive voltage circuit to a good ground. Refer to Circuit Testing and Wiring Repairs .

Is the voltage within the specified range?

10-14 V

Go to Step 4

Go to Step 5

4

Test the deceleration sensor ground circuits of the electronic brake control module (EBCM) for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 7

Go to Step 6

5

Locate and repair the following in the ignition positive voltage circuit of the deceleration sensor.

    • An open
    • High resistance
    • Short to ground

Did you find and correct the condition?

--

Go to Step 7

--

6

Replace the deceleration sensor. Refer to Deceleration Sensor Replacement .

Did you complete the replacement?

--

Go to Step 7

--

7

  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 text.

Does the DTC reset?

--

Go to Step 2

System OK