Idle Up Circuit

The Electronic Brake Control Module (EBCM) is linked to the Engine Control Module (ECM) through an Idle-up circuit.
During an Antilock Brake System (ABS) stop on icy road conditions, the EBCM commands the ECM to increase idle speed.
This will reduce "engine braking", thus preventing early wheel lock-up and enhance brake modulation.
An increase in idle speed occurs when the transfer case is any of the 4WD ranges.