Chevy Communication Breakdown
This bulletin applies to 2010-2013 Chevy Camaro models. In rare cases, a customer may report an intermittent fluctuation of IP gauges, no crank, SES light on, or various IP warning indicators or messages. Technicians may find that there is no communication to various High Speed LAN modules. Communication to control modules may be random and could change during inspection.
Any of these concerns could be caused by a short to ground or an open on either of the two High Speed LAN circuits 2500 and/or 2501.
There are two locations on the vehicle to inspect, depending on what vehicle options are present.
The first area of concern is the engine wiring harness under the ECM. Check for possible chaffing of this harness on the inner fender panel. If chaffing found, repair the wire(s), install protective conduit on this area of the harness and relocate the harness away from the panel.
The second area of concern relates to vehicles equipped with an automatic transmission. A HSLAN circuit terminal may not be seated properly in the round TCM connector located on the transmission. Inspect the TCM connector for any data line circuits that may not be fully seated in the plastic connector. If this concern is found, inspect the condition of both halves of the connector as well as both the male and female terminals. If the female terminal was not seated correctly, push on the wire until the terminal clicks back into position.
Lightly tug on the wire to verify seating. If the male terminal or the TCM half of the connector is damaged, the entire TCM will require replacement. This module is internal to the automatic transmission assembly.