No Communication with Electronic Brake Control Module

No Communication with Electronic Brake Control Module

Circuit Description

Serial data is transmitted/received by the electronic brake control module (EBCM) through terminal 7. The EBCM is supplied with constant battery feed voltage through terminals 9 and 25, and switched ignition voltage through terminal 4. The EBCM ground is provided through terminal 8 and 24.

Diagnostic Aids

Typical causes of no communication with the EBCM:

* Poor terminal contact at the EBCM
* Loss of EBCM ground to terminal 8 and 24
* Loss of battery voltage at EBCM terminals 9 and/or 25
* Loss of ignition voltage at EBCM 4
* Open/grounded data line
* Data line with high resistance

Step 1 - Step 7:

Step 8 - Step 14: