2009 Cadillac STS-V Owner's Manual - Page 238

ENGINE HOT - AC (Air Conditioning) OFF This message displays when the engine coolant becomes hotter than the normal operating temperature. See Engine Coolant Temperature Gage on page 3-65. To avoid added strain on a hot engine, the air conditioning compressor is automatically turned off. When the coolant temperature returns to normal, the air conditioning compressor turns back on. You can continue to drive your vehicle. If this message continues to appear, have the system repaired by your dealer/retailer as soon as possible to avoid damage to the engine. ENGINE POWER REDUCED This message displays when the engine power is being reduced to protect the engine from damage. There could be several malfunctions that might cause this message. Reduced engine power can affect the vehicle's ability to accelerate. If this message is on, but there is no reduction in performance, proceed to your destination. The performance may be reduced the next time the vehicle is driven. The vehicle may be driven at a reduced speed while this message is on, but acceleration and speed may be reduced. Anytime this message stays on, take the vehicle to your dealer/retailer for service as soon as possible. 3-84