DTC C1242 Pump Motor Circuit Open. Chevrolet PJJ 2000

For 1990-2009 cars

### Circuit Description

The EBCM relay supplies power to the solenoid valves and pump motor. The EBCM relay activates when the ignition is turned to the ON position. Power is available to the solenoid valves and pump motor through the relay via the battery positive voltage circuit. The EBCM relay remains engaged until the ignition switch is turned to the OFF position or until the EBCM detects a malfunction which requires the system to be disabled.

### Conditions for Running the DTC

• | The switched battery voltage is greater than 8.0 volts.

• | The EBCM relay is ON.

• | The pump motor is commanded OFF.

### Conditions for Setting the DTC

The voltage across the pump motor is between 1.7 and 10.2 volts for 2 seconds.

### Action Taken When the DTC Sets

The following actions occur:

• | The EBCM disables the ABS for the duration of the ignition cycle.

• | The ABS warning indicator turns ON.

• | A malfunction DTC is stored.

### Conditions for Clearing the DTC

• | The condition for setting the DTC is no longer present and the scan tool Clear DTCs function is used.

• | The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

### Diagnostic Aids

• | Possible causes for DTC C1242 to set are:

- | Pump motor open.

- | An internal EBCM malfunction exists.

• | The pump motor is an integral part of the BPMV and is not serviced separately.

### Test Description

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

1. This step uses the scan tool to test if the pump motor can be commanded ON and OFF.

2. This step verifies the resistance of the pump motor.

3. This step determines whether the DTC resets.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the ABS Diagnostic System Check? | -- | Go to Step 2 | Go to ABS Diagnostic System Check

2

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. With the scan tool, command the pump motor ON and OFF. This is done with the Pump Motor Test located in ABS Special Functions.

Does the pump motor turn ON and OFF with each command?

--

Go to Testing for Intermittent and Poor Connections in Wiring Systems

Go to Step 3

3

1. Turn OFF the ignition.
2. Remove the EBCM from the BPMV. Refer to Electronic Brake Control Module Replacement.
3. Measure the resistance between the pump motor control circuits.

Does the resistance measure less than the specified value?

5 ohms

Go to Step 4

Go to Step 6

4

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

Does the DTC reset?

--

Go to Step 5

Go to Testing for Intermittent and Poor Connections in Wiring Systems

5 | Replace the EBCM. Refer to Electronic Brake Control Module Replacement. Did you complete the repair? | -- | Go to Step 7 | --
6 | Replace the BPMV. Refer to Brake Pressure Modulator Valve Replacement. Did you complete the repair? | -- | 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