For 1990-2009 cars
ABS Components
Antilock Brake System Schematics
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

### Circuit Description

Four-way serial communication is sent back and forth between the EBCM, IPC, PCM, and the BCM. A message from the IPC is sent to the BCM within seven seconds after ABS initialization. A serial communication failure does not allow the proper warning indicator commands to be sent back to the IPC.

### Diagnostic Aids

Use the Lamp Test function of the Scan Tool in order to turn the indicator ON and OFF while looking for an intermittent malfunction.

Thoroughly inspect any circuitry that may cause the intermittent complaint for the following conditions:

• | Backed out terminals

• | Improper mating

• | Broken locks

• | Improperly formed or damaged terminals

• | Poor terminal-to-wiring connections

• | Physical damage to the wiring harness

### Test Description

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

1. This test ensures that the instrument cluster can operate the LOW TRAC indicator.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
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. Install a scan tool.
3. Turn ON the ignition, with the engine OFF.
4. Select the Body menu and then IPC on the scan tool.
5. Select Lamp Test on the scan tool.
6. With the scan tool, turn the warning indicators ON and OFF

Does the LOW TRAC indicator turn ON and OFF?

--

Go to Step 3

Go to Step 4

3 | 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 7 | Go to Step 5
4 | Inspect for poor connections at the harness connector of the instrument cluster (IPC). 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 7 | Go to Step 6
5 | Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Did you complete the repair? | -- | Go to Step 7 | --
6 | Replace the instrument cluster (IPC). Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console. Did you complete the repair? | -- | Go to Step 7 | --
7 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 2