help with Check Engine Light..on a 02 a6 3.0
 

ok so i got a check engine light on. scanned it with the vaCcom came up p1296 cooling system malfunction. im not overheating.. so highly dought its the thermostat.. in the morning i turned the key but didnt start the motor and the fan just cuts on.. so maybe its the cooling fan control module? but before i go spending 300$ on the part. i was wondering if the ECT sensor would cause the fan to just cut on while the car is cold??? i was thinking maybe it would do that because if the sensor is bad it could tell the car its too hot. is this possible????? please help thanks

"several possibly issues for this fault. 1. your ect, back of the cylinder head if it's not green you need to replace it. the green sensor is the updated part. 2. a stuck open t-stat. an engine not warming up withing the specified range will set this fault.3 a water pump impeller that has separated from the shaft. the impeller is plastic and the shaft is metal, pretty common." warrantysucks http://forums.audiworld.com/18t/msgs/4761.phtml

"P1296 indicates a Malfunction In The Cooling System. For this malfunction the PCM does not turn the Malfunction Indicator Light (MIL) unless the malfunction is recognized after another engine start.

The two things that will set this DTC is a defective Engine Coolant Temperature (ECT) sensor or the thermostat. This would cause the symptoms you described to me." http://autorepair.about.com/library/faqs/bl210i.htm

Sorry I can't be of more help but is sounds to me like you should start with the coolant temp sensor and go from there.

a water pump impeller that has separated from the shaft. the impeller is plastic and the shaft is metal, pretty common."

if this was the case would i over heat or see coolant under the car? or how would i be able to tell?.. i checked the cts and its green but it still might be bad... also if it were the water pump impeller i would just replace the water pump or do i need more parts??

If your water pump failed, you would overheat for sure. How many miles are on your car? I believe my CTS is green and mine is failing as well.

I don't believe you water pump has failed, but just fyi you would need to buy all the parts for a timing belt change.