Test I: The Front Controls Interface Module (FCIM) Illumination Does Not Operate Correctly

PINPOINT TEST I: THE FRONT CONTROLS INTERFACE MODULE (FCIM) ILLUMINATION DOES NOT OPERATE CORRECTLY

Normal Operation
The front controls interface module (FCIM) receives the illumination signal from the smart junction box (SJB), and dims the illumination based on the position of the dimmer switch. The illumination signal is sent via the medium speed controller area network (MS-CAN).

- DTC U0140 (Lost Communication With Body Control Module [GEM]) - sets when the FCIM is missing messages from the SJB for ignition state, illumination, or delayed accessory. Because a missing ignition state or delayed accessory signal would cause multiple symptoms (since many modules would report this error), only the illumination signal is diagnosed in this pinpoint test.

In order for the FCIM to set DTC U0140, the illumination signal must be missing for greater than 5 seconds. In the event this signal is lost, the FCIM defaults to full nighttime brightness, resulting in a symptom of the FCIM being unable to dim.

This pinpoint test is intended to diagnose the following:
- Backlighting system concern
- FCIM

I1-I2: