No Communication with Electronic Brake Control Module

No Communication with EBCM
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 11:

Step 12 - Step 14: