Colwell

Hi guys, My a4 cabriolet 1.8t has been idleing rough recently. I ran the VAG com and found alot of problems, I cleared the codes and started again.

P1291 coolant temp sensor at radiator output signal too large appeared along with p1292 map controlled engine cooling thermostat open circuit no signal?
Intake air temp sensor P0112 signal too low also appeared.

Not sure where too start really only had the Audi 6 weeks. If anyone has come accross these problems and has the answers they would be greatly appreciated.

Thanks guys

Oneplank

Not sure what vintage is your A4, but I have replaced the coolant sensor in my 1998 2.8L A4 twice. It's a common problem.

Colwell

Hi my Audi is on a 53 plate.

extetty

Has anyone had their coolant temp sensor just go bad? ive got a 95 yj 4.0 and it was fine. i pulled the head to do some some work on the pushrods and rocker arms. Whenn i finished and turned the ignition on did not crank the temp guage was at around 230. started it and it immediatley went to max. Checked codes and it read a 22 which is coolant temp sensor. Just did not know what i could have done to cause it.

malinowskiski

I had a bad coolant temp sensor. Was getting this code:
17704 - Error in Mapped Cooling System (check Temp-Sensor and Thermostat)
P1296 - 35-00 - -

As far as I can tell, the bad coolant sensor for me was largely asymptomatic. The gauge would take forever to move, as long as 20 minutes of continuous freeway driving, now it will move to operating temp after about 5 minutes of light driving in town after being completely cold. I thought I would get better MPGs as the fuel trim would adjust from warming to operating much quicker, but has been about the same.

If your coolant temp sensor has gone bad, order a new one and put her in. They are about $10 on ECS before shipping and a piece of cake to change.. at least that was my experience with my B5 S4.