Circuit Description

WARNING: This page is about a different car, the 2000 Isuzu Hombre. However, it is still accessible from the selected car via links, so may be relevant.

A Class II serial data communications system is used to allow various modules to communicate and share information with each other. Each bit of information has 2 lengths, long or short. This allows vehicle wiring to be reduced and transmission and reception of multiple signals over a single wire. Messages carried on a Class II serial data streams are also prioritized. If 2 messages attempt to establish communications on data line at the same time, message with a higher priority will continue. Message with a lower priority will wait. If a module cannot respond to the PCM, a DTC will set.

Conditions for setting DTC are:

PCM cannot communicate with Electronic Brake Control Module (EBCM) for duration of 15 after previously establishing communications with EBCM.
Ignition switch in cranking position for 15 seconds with engine not rotating due to starter or electrical malfunction.