For 1990-2009 cars

### Circuit Description

The EBCM illuminates the ECU LED when the voltage supplied to the EBCM is less than 9 volts or when the EBCM detects an internal malfunction.

### Conditions for Running the Diagnostic Fault

The ignition is ON.

### Conditions for Setting the Diagnostic Fault

Either of the following conditions may cause the EBCM to illuminate the ECU LED.

• | The voltage supplied to the EBCM drops below 9 volts rendering the EBCM inoperative.

• | The EBCM detects an internal malfunction.

### Action Taken When the Diagnostic Fault Sets

• | The ABS indicator turns ON.

• | The ABS is disabled.

• | The EBCM illuminates the ECU LED.

### Conditions for Clearing the Diagnostic Fault

• | Repair the condition responsible for illuminating the status lamps.

• | Perform the Status Lamps Reset Procedure.

### Diagnostic Aids

Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Refer to the following:

• | Testing for Electrical Intermittents

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

• | Connector Repairs

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Air Antilock Brake System Schematics
1 | Did you perform the ABS Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Air ABS
2 |

1. Perform the magnetic reset procedure. Refer to Status Lamp Resetting .
2. Operate the vehicle within the Conditions for Running the Diagnostic Fault.

Does the red ECU LED remain illuminated?

Go to Step 3

Go to Diagnostic Aids

3 | Inspect for poor connections at the harness connectors 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 5 | Go to Step 4
4 | Important: Following EBCM replacement, perform the EBCM self-configuration procedure. Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Did you complete the replacement? | Go to Step 5 | --
5 |

1. Perform the magnetic reset procedure. Refer to Status Lamp Resetting .
2. Operate the vehicle within the Conditions for Running the Diagnostic Fault.

Does the red ECU LED remain illuminated?

Go to Step 2

System OK