For 1990-2009 cars

### Circuit Description

The instrument cluster controls the operation of the Antilock Brake System (ABS) indicator. The electronic brake control module (EBCM) reports the desired status of the ABS indicator via serial data messages. The EBCM supplies ground through the circuit when the ABS is operating properly. When there is a problem with ABS that should turn on the ABS indicator, the EBCM opens the ABS indicator signal circuit. Using the serial data messages the instrument cluster will determine whether to turn on the ABS indicator.

### Test Description

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

1. Use the scan tool to check the normal state of the ABS indicator control circuit.

2. Ensures that the instrument panel cluster (IPC) can operate the ABS indicator.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: Antilock Brake System Schematics Connector End View Reference: Antilock Brake System Connector End Views or Master Electrical Component List
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 | Inspect the electronic brake control module (EBCM) ground, ensure the ground terminal is clean and torqued to the proper specification. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 3
3 |

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. With a scan tool, observe the Antilock Brake System (ABS) Warning Indicator parameter in the dynamic rear proportion (DRP)/ABS/Traction Control System (TCS) data list.

Does the scan tool display Off?

--

Go to Step 4

Go to Step 5

4 |

1. Turn OFF the ignition.
2. Turn ON the ignition, with the engine OFF.
3. Observe the ABS indicator on the instrument panel cluster (IPC) during the displays test.

Does the ABS indicator illuminate during the displays test and then turn OFF?

--

Go to Testing for Intermittent Conditions and Poor Connections

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 . Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 7
6 | Inspect for poor connections at the harness connector of the IPC. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 8
7 | Replace the EBCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 9 | --
8 | Replace the IPC. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 9 | --
9 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 2