Diagnostic Fault Information

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Cadillac Escalade EXT. However, it is still accessible from the selected car via links, so may be relevant.

Component	Cause	DTCs
Engine	Engine coolant level low Incorrect engine coolant Old coolant or incorrect concentration level Cooling system leak Radiator hose kinked or pinched Loose, missing, or damaged radiator air seals or deflector - poor air flow The radiator and A/C condenser has air flow obstructions to include large amount of bent fins The cooling fans do not operate Inspect the engine mechanical for worn, leaking, cracked cylinder heads, or engine block	P1258
Transmission	Vehicle Overload or Beyond Capacity Towing: Vehicle is overloaded Vehicle is towing beyond capacity Towing in wrong gear Vehicle modifications	P0218
	Heat transfer: Engine overheating Cooler restrictions - radiator has restricted flow/blockage Restricted air flow Vehicle modifications Aftermarket auxiliary cooler installed incorrectly, incorrect flow direction - reversed flow Restricted, blocked, or pinched transmission cooler lines.	P0218
	Transmission Abuse: Engine overheating Excessive brake torque maneuvers Vehicle overloaded Vehicle is towing beyond capacity Vehicle modifications	P0218
	Vehicle Damage: Damage to vehicle under carriage Transmission bottom pan damage Restricted air flow	P0218
	Transmission Fluid: Fluid leaks Low fluid level Contaminated or poor fluid quality	P0218
	Torque Converter: Inefficient pump Torque converter failure - stator, pump, clutch, ballooning or heat damaged Stuck on or locked up Converter damage	P0218
	Low Pump Output: Low fluid level Blocked, damaged or loose filter Pinched or restricted cooler lines Restricted cooler - damage or debris Inefficient pump - worn	P0218
	Clutch Slippage: Low fluid level Low Pump Output	P0218