In-chassis engine compression release brake diagnostic test and electronic control module using the same

A method of performing an in-chassis engine compression release brake diagnostic test comprising the steps of:

• providing an engine having an electronic control module and a plurality of cylinders;
• providing a fuel injector and an engine compression release brake in association with at least a portion of said plurality of said cylinders;
• determining at least one of an expected fuel injector response and an expected engine response;
• testing one of said engine compression release brakes, at least in part by operating a first portion of said cylinders in a power mode during a test cycle, operating a second portion of said cylinders in a braking mode during said test cycle, and determining at least one of a trial fuel injector response and a trial engine response;
• and
• comparing at least one of said trial fuel injector response with said expected fuel injector response and said trial engine response with said expected engine response.

An electronic control module for an engine having a plurality of cylinders, and a fuel injector associated with each cylinder and an engine compression release brake associated with selected ones of said plurality of cylinders, comprising:

• a means for activating and deactivating a portion of said fuel injectors during a test cycle;
• a means for activating and deactivating a portion of said engine compression release brakes during said test cycle;
• and
• at least one of a means for comparing a trial fuel injector response with an expected fuel injector response and a means for comparing a trial engine response with an expected engine response.