GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The system relay is energized when the ignition is ON. The system relay supplies voltage to the solenoid valves and the pump motor. This voltage is referred to as the system voltage.

The electronic brake control module (EBCM) controls each solenoid valve by grounding the solenoid.

The EBCM controls the pump motor by grounding the control circuit. 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.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C1217 Pump Motor Shorted to Ground

Conditions for Running the DTC

    • The pump motor has been commanded OFF for 1 second.
    • The system voltage is greater than 9.36 volts.

Conditions for Setting the DTC

One of the following conditions exists for 0.2 seconds:

    • The voltage across the pump motor is greater than 10.2 volts.
    • The pump motor low side voltage is less than 2.7 volts.

Action Taken When the DTC Sets

    • The EBCM disables the ABS for the duration of the ignition cycle.
    • The ABS indicator turns ON.
    • The DRP does not function optimally.

Conditions for Clearing the DTC

    • The condition for the DTC is no longer present and the DTC is cleared with a scan tool.
    • The electronic brake control module (EBCM) automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Diagnostic Aids

    • This DTC determines if there is a short in the pump motor control circuit.
    • The pump motor is integral to the BPMV. The pump motor is not serviceable.

Test Description

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

  1. This step tests the pump motor circuits of the BPMV for a short to the housing of the BPMV.

Step

Action

Value(s)

Yes

No

Schematic Reference: Antilock Brake System Schematics

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Turn OFF the ignition.
  2. Disconnect the electronic brake control module (EBCM) harness connector.
  3. Connect the J 39700 Universal Pinout Box using the J 39700-99 Breakout Box Adapter to the EBCM harness connector only.
  4. Test both ground circuits of the EBCM including the EBCM ground for a high resistance or an open.

Did you find and correct the condition?

--

Go to Step 8

Go to Step 3

3

  1. Remove the EBCM from the brake pressure modulator valve (BPMV). Refer to Electronic Brake Control Module Replacement .
  2. Measure the resistance from both pump motor control circuits of the BPMV to the housing of the BPMV. Refer to Circuit Testing in Wiring Systems.

Does the resistance measure less than the specified value?

5 ohms

Go to Step 4

Go to Step 5

4

Inspect for poor connections at the connector of the BPMV. 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 6

5

Inspect for poor connections at the harness connector of the EBCM. 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 7

6

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

Did you complete the repair?

--

Go to Step 8

--

7

Replace the EBCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

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