GM Service Manual Online
For 1990-2009 cars only

Object Number: 234328  Size: MF
ABS Components
Cell 44: DLC and Solenoids
Handling ESD Sensitive Parts Notice

Circuit Description

DTC C1281 identifies a solenoid that cannot be energized due to a short to voltage in the solenoid circuitry. The malfunction can affect ABS operation since the flow of brake fluid to the wheel cylinder cannot be stopped. The unstoppable flow of brake fluid to the wheel cylinder makes ABS operation for that channel impossible.

Conditions for Setting the DTC

    • DTC C1281 can set only when the brake solenoid is commanded ON.
    • A malfunction exists if the EBCM detects the right front brake solenoid valve control circuit voltage is not within specifications.

Action Taken When the DTC Sets

    • A malfunction DTC stores.
    • The ABS disables.
    • 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.
    • 100 drive cycles pass with no DTCs detected. A drive cycle consists of starting the vehicle, driving the vehicle over 16 km/h (10 mph), stopping and then turning the ignition OFF.

Diagnostic Aids

Use the enhanced diagnostic function of the Scan Tool in order to measure the frequency of the malfunction.

Any circuitry that is suspected of causing the intermittent complaint should be thoroughly checked for improper mating, improperly formed or damaged terminals, poor terminal to wiring connections, or physical damage to the wiring harness.

Test Description

  1. This test checks for a short to voltage in the solenoid circuit.

  2. This test checks the solenoid for the proper resistance value.

  3. This test determines if the malfunction is caused by the EBCM.

Step

Action

Value(s)

Yes

No

Important: Zero the J 39200 test leads before making any resistance measurements. Refer to the J 39200 user's manual.

Important: Difficulty may occur when trying to locate the intermittent malfunctions in the wheel speed sensor circuit.

Do not disturb any of the electrical connections. Change electrical connections only when instructed to do so by a step in the diagnostic table.

Changing the electrical connections at the correct time will ensure that an intermittent electrical connection will not be corrected until the source of the malfunction is found.

1

Was A Diagnostic System Check-ABS performed?

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Go to Step 2

Go to Diagnostic System Check - ABS

2

  1. Turn the ignition switch to LOCK.
  2. Disconnect the EBCM harness connector C1.
  3. Turn the ignition switch to ON.
  4. Use the J 39200 in order to measure the voltage between the EBCM harness connector C1 terminal B6 and ground.

Is the voltage within the specified range?

0-1 V

Go to Step 3

Go to Step 5

3

  1. Turn the ignition switch to LOCK.
  2. Disconnect the right front ABS solenoid valve connector.
  3. Use the J 39200 in order to measure the resistance between the right front solenoid valve terminals A and B.

Is the resistance within the specified range?

2.5-5.0 ohms

Go to Step 4

Go to Step 6

4

  1. Inspect the RED/WHT wire between the EBCM and the RF ABS solenoid and the EBCM connector C1 for damage which may result in a short to voltage with all the connectors connected.
  2. Reconnect connector(s).
  3. Start the engine.
  4. Drive the vehicle at 16 km/h (10 mph).
  5. Stop the vehicle and turn the ignition switch to LOCK.
  6. Repeat drive cycle (steps 3, 4 and 5).
  7. Turn the ignition switch to ON.
  8. Using a scan tool, check for DTCs.

Did DTC C1281 set during the past three ignition cycles?

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Go to Step 7

Go to Diagnostic System Check - ABS

5

Repair the short to voltage in the RED/WHT wire between the EBCM and the RF ABS solenoid. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

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Go to Diagnostic System Check - ABS

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6

Replace the RF ABS solenoid. Refer to Brake Solenoid Valve Replacement .

Is the repair complete?

--

Go to Diagnostic System Check - ABS

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7

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

Is the repair complete?

--

Go to Diagnostic System Check - ABS

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