18-015-15

Malfunction Indicator Lamp (MIL) Illumination And/Or Intermittent No Crank No Start This bulletin involves inspecting the Charge Air Cooler (CAC) system for excessive water and/or ice and drying the CAC components if needed. It also involves installing a winter front cover. A small number of customers may experience a MIL illumination when ambient temperatures fall below 32°F (0 °C). Upon further inspection, a technician may find the following Diagnostic Trouble Codes (DTCs). ? P0299 - Turbocharger Underboost Condition ? U1424 - Implausible Engine Torque Signal Received In addition, customer vehicle may come in with a no crank/no start. This may have occurred after the vehicle has been driven for an extended period of time in extremely low ambient and then allowed to sit overnight. Further diagnosis may indicate a possible inoperative starter. DISCUSSION: A possible cause of these concerns may be contributed to internal icing of the Charge Air Cooler (CAC) system and intake manifold. Icing will occur because warm, moist air from the turbo charger is being rapidly cooled and the moisture is then condensed into liquid by the CAC. The liquid is then distributed into the rest of the intake system, which is operating at ambient temperature, where it will then freeze. Vehicles that are driven for extended periods of time are susceptible to higher amounts of ice build up within the intake manifold. Once the vehicle is turned off and allowed to sit, the ice formation in the intake will begin to melt due to the elevated underhood temperatures. The moisture will then run down the intake runners and accumulate in the combustion chamber through an open intake valve causing the engine to hydro-lock. To prevent icing in the CAC system when vehicle is operated in low ambient temperatures, it is highly recommended that the vehicle have winter front cover installed. This raises the CAC outlet temperatures above freezing which will help reduce condensation build up.