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 C1244 Deceleration Sensor Circuit Open or Shorted

Conditions for Running the DTC

DTC C1244 can be set anytime the ignition switch is in the ON position.

Conditions for Setting the DTC

The EBCM detects an open or a short in the deceleration sensor circuitry.

Action Taken When the DTC Sets

The ABS 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 short in deceleration signal circuit
    • 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
    • An internal EBCM malfunction

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

Test Description

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

  1. Test the deceleration sensor voltage circuit for a high resistance, an open, or a short.

  2. Test the deceleration sensor ground circuit for a high resistance, an open, or a short.

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?

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Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Disconnect the deceleration sensor connector (AWD) or yaw rate sensor connector (except AWD).
  2. Turn ON the ignition, with the engine OFF.
  3. Measure the voltage of the sensor voltage circuit to a good ground. Refer to Circuit Testing and Wiring Repairs .

Is the voltage within the specified range?

4.5-5.5 V (AWD), 10-14 V (except AWD

Go to Step 5

Go to Step 3

3

Test the sensor voltage circuit for the following:

    • An open
    • High resistance
    • Short to ground

Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 8

Go to Step 4

4

Is the vehicle equipped with AWD?

--

Go to Step 7

Go to Step 5

5

Test the sensor ground circuit for a high resistance or open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 8

Go to Step 6

6

Replace the deceleration sensor (AWD) or yaw rate sensor (except AWD). Refer to Deceleration Sensor Replacement or Vehicle Yaw Sensor Replacement .

Did you complete the replacement?

--

Go to Step 8

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7

Replace the brake pressure modulator valve (BPMV). Refer to Brake Pressure Modulator Valve Assembly Replacement .

Did you complete the replacement?

--

Go to Step 8

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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 text.

Does the DTC reset?

--

Go to Step 2

System OK