Check Engine light and Noisy Fan

[daryllafferty]

My Check Engine light came on yesterday. About the same time, I noticed that the car was very noisy. There was a fan running at high speed. At first I thought it was just the air conditioner trying to keep up with the 95 degree weather, but that didn't make sense.

Took it in to the Chevy dealer today (I didn't know about using OnStar). They checked it out, and said that the engine intake temperature sensor was failing, so the car thought the ambient air was very hot and was trying to keep it cool by running the fan full speed.

They didn't have a new sensor in stock, so I'll have to live with a noisy Volt until it comes in. At least I can continue to drive it.

BTW, the service adviser told me they have a Volt loaner they reserve for Volt customers. That's pretty cool!

Edit: Just plugged my CodeKey in to the port, and saw that the error is P0111, "Intake Air Temperature".

[DonC]

Sorry to hear about the sensor failure. Very cool about the Volt loaner.

[TheProgrammerGuy]

Be sure to keep your eye on it. I recently had an Audi that did this only the fan would come on while the car was parked and run the battery down completely. And just like Chevrolet might tell you, Audi told me that that couldn't happen until they witnessed it.

[reddog]

I actually have run into this problem before, and a faulty sensor is often not the cause. When you return for service, have the technician check the wiring just behind the connector of the intake air sensor. I've seen the wires break inside the insulation and create an open for the iat/maf circuits. It's easily missed because the wires are covered by heavy tape. Once the tape is removed, using a small screwdriver, give each wire a gentle tug away from the connector body. If one of the wires breaks, the connector will have to be replaced.

[WopOnTour]

I actually have run into this problem before, and a faulty sensor is often not the cause. When you return for service, have the technician check the wiring just behind the connector of the intake air sensor. I've seen the wires break inside the insulation and create an open for the iat/maf circuits. It's easily missed because the wires are covered by heavy tape. Once the tape is removed, using a small screwdriver, give each wire a gentle tug away from the connector body. If one of the wires breaks, the connector will have to be replaced.

Not very likely in this case. A P0111 is an IAT "performance" code where the sensors value is not correlating with expected values (as opposed to other DTCs where a wiring fault like a broken wire or bad connection would cause).Most likley a skewed sensor resistance value. There's an outside possibly that increased resistance due to corrosion or something like that in the signal circuit that might cause this DTC but not likely on such a new car. Presumably the dealer tech would have followed the P0111 diagnostic steps and completed a couple of simple circuit tests at the mass airflow sensor connector (the IAT is integral to the MAF on the Volt) to eliminate signal circuit resistance as a possibility. There may also be some sort of calibration issue given you are in AZ currently experiencing record high temperatures.
Barring that they will likely just replace the MAF sensor !
Let us know if it all goes well for you Daryl
WOT

EDIT: On July 30 2012 GM has released a preliminary bulletin to dealers that relates to tis P0111 DTC triggering under certain HOT ambient conditions. This bulletin PIC5708 indicates that engineering is currently examining the issue and that a revised calibration may need to be made available for people in extrem hot conditions (greater than 110F) If you encounter this DTC (from a DT request via Onstar) I suggest you first CALL your dealer and request if there is any update to the resolution status indicated in the bulletin. No use scheduling a dealer visit when they cannot (at this time) do much of anything.

[Gregrt]

I just had the same error happen to me, when i pluged in my volt the fan took off on high speed. Like the car was really HOT, but it was not. So i just dropped it off at the dealer and got a loaner. Interesting, never saw my dealer after I purchased my Prius. I hope I don't see my Chevy dealer any after this.

[Brittt1]

Same thing occurrred to me on the way to work, noisy fan and check engine light...I guess Ill take it in soon unless it fixes itself. temperature hit 105 when it happened and its as humid as hell.

[daryllafferty]

I started this thread. The CE light came on a couple more times that day, then never again. About 3 weeks later the dealer called that they had the new sensor in, so I had it replaced, but I will probably never know what really caused the problem.

[dgb40356]

Just dropped mine off today with the same error. Service department gave me a loaner but it wasn't a Volt. They ask to keep it over night and are waiting to get a call back from engineering about the error.

[ari_c]

I just noticed the check engine light on my Volt this afternoon. OnStar ran the diagnostics and it was the same error code P0111. When I pulled into my garage the fan was incredibly loud. I'll be bringing it in for service first thing in the morning. Hopefully I won't get another HHR as a loaner.