#14262: Special Coverage Adjustment – Accessory Power Module May Not Initialize in Cold Temperature – (Oct 27, 2014)
On some 2008-2013 model year Chevrolet Tahoe and GMC Yukon, and 2009-2013 model year Cadillac Escalade, Chevrolet Silverado LD, and GMC Sierra LD hybrid 2-mode (HP2) vehicles, the accessory power module (APM) may not initialize when the vehicle is started in cold temperatures and the APM is cold. Once the APM warms up, it will initialize and perform as designed. However, during the time that the APM is not operational, it could result in a loss of power steering assist and the battery may not charge. If this condition occurs, the Service Power Steering, Service Hybrid System, or Service Battery Charging System message will appear in the driver information center, the malfunction indicator lamp and red battery telltale may illuminate, and DTC U1821 and U182A will be present.