GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2002 🢒 Eldorado 🢒 DTC 🢒 DTC C1242 or C1243

Circuit Description

The pump motor is grounded through the ground stud on the BPMV. The EBCM controls the pump motor by energizing the pump motor relay. The pump motor relay then supplies voltage to the pump motor. The pump serves 2 purposes:

    • Transfers brake fluid from the brake calipers to the master cylinder reservoir during pressure decrease events.
    • Transfers brake fluid from the master cylinder reservoir to the brake calipers during pressure increase events.

Conditions for Running the DTC

C1242

The pump motor is commanded OFF.

C1243

The pump motor is ON for at least 0.15 seconds.

Conditions for Setting the DTC

C1242

One of the following conditions exists:

    • The voltage across the pump motor is between 3.3-5.2 volts for 2 seconds.
    • The pump motor ground resistance is greater than 6900 ohms.

C1243

The pump motor is stalled or turning slowly.

Action Taken When the DTC Sets

If equipped, the following actions occur:

    • The EBCM disables the ABS/TCS/VSES for the duration of the ignition cycle.
    • The ABS indicator turns ON.
    • The Traction Control indicator turns ON.
    • The DIC displays the Service Stability System message.

Conditions for Clearing the DTC
    • The condition for the DTC is no longer present (the DTC is not current) and you used the scan tool Clear DTC function.
    • The condition for the DTC is no longer present (the DTC is not current) and you used the On-Board Diagnostics Clear DTC function.
    • The EBCM automatically clears the history DTC when a current DTC is not detected in 50 consecutive drive cycles.

Diagnostic Aids

The pump motor is integral to the BPMV. The pump motor is not serviceable.

Test Description

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

  1. Tests the pump motor ground.

    2.

  2. Tests the pump motor ground through the BPMV.

Step

Action

Values

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. Measure resistance between the motor ground stud and the battery negative terminal.

Is the resistance less than the specified value?

2 ohms

Go to Step 3

Go to Step 7

3
  1. Disconnect the EBCM connector.
  2. Remove the EBCM from BPMV.
  3. Inspect the EBCM to BPMV connector for the following conditions, which could cause an intermittent:
    4. • Damage
    • Corrosion
    • Poor terminal contact
    • The presence of brake fluid

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 8

Go to Step 4

4

  1. Install the J 41247 BPMV pinout box to the BPMV connector.
  2. Measure the resistance between the pump motor control circuit of the J 41247 BPMV pinout box and the pump motor ground stud.

Is the resistance within the specified range?

0.2-10 ohms

Go to Step 5

Go to Step 6

5

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

Did you complete the repair?

--

Go to Step 8

--

6

Replace the BPMV. Refer to Brake Pressure Modulator Valve Replacement .

Did you complete the repair?

--

Go to Step 8

--

7

Repair the open in pump motor ground circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 8

--

8
  1. Use the scan tool in order to clear the DTCs.
  2. With the scan tool, perform the Automated Test.

Does the DTC reset?

--

Go to Step 2

System OK