Air Intake Temperature Sensor

[aerial_22]

I am having problems with my air intake temperature sensor on my 1999 Grand Am SE 3.4L. I have had it replaced, but my check engine light remains on. I am concerned when the sensor went bad that it shorted out the contact for this sensor on the car's main computer. Anyone had a similar experience?

I am also a little ticked off at the moment. I had my intake manifold gasket replaced back in 2001, and now it is leaking again. As much as this seems to be a common problem with this car you would think Pontiac would address the issue. I am now going to have have to pay $600-800 again to have it replaced.

[dfmote]

I feel your pain and you are right. I also have a 3.4L V6 and as of right now Im not sure if my intake gasket is leaking or not (stated in a diff thread) but I have talked to many people and they all say that this is a very common problem with the 3.4L GM Engines. Its a design flaw and GM should be shot and if you have noticed they stopped making Grand Ams in 2006. Im not sure why but Id love to know.

[aerial_22]

Yeah, when I first had the problem with my intake manifold gasket back in 2001, I was told by the Pontiac dealer that the material used for the seal when the car was built was defective. That being said, Pontiac was not going to cover the repair under warranty, or as a recall. To me it is a design flaw, and they should be accountable.

[xeroinfinity]

Welcome to the club, my 99' too has had the intake gaskets replaced, 4 damn times in the past 3-4 yrs.
The 3.4's should hav had something changed to prevent the gaskets from blowing out. Its wierd because the 3.1's didnt leak/blow that many gaskets.

[aerial_22]

Wow! I don't feel so bad now! At least I have only had to replace mine twice. Hopefully this will be the last time.

[01Z]

Originally Posted by aerial_22

I am having problems with my air intake temperature sensor on my 1999 Grand Am SE 3.4L. I have had it replaced, but my check engine light remains on. I am concerned when the sensor went bad that it shorted out the contact for this sensor on the car's main computer. Anyone had a similar experience?

The AIT sensor should be a passive device. In other words, no voltage should be present and therefore it cannot harm your ecm/pcm (computer). Additionally, the AIT sensor can be unplugged and overriden with a cheap, 20 cent resistor from radio shack inserted into the cable end. I don't recommend it but it is considered a back yard performance trick.

If your SES remains on, you can reset the persistant code by removing your pcm batt fuse (with the engine off) for 30 seconds. If the SES comes back on then it is time to go to autozone and have the codes scanned (free) and see what else is illuminating the icon.

Regards

[aerial_22]

Originally Posted by 01Z

The AIT sensor should be a passive device. In other words, no voltage should be present and therefore it cannot harm your ecm/pcm (computer). Additionally, the AIT sensor can be unplugged and overriden with a cheap, 20 cent resistor from radio shack inserted into the cable end. I don't recommend it but it is considered a back yard performance trick.

If your SES remains on, you can reset the persistant code by removing your pcm batt fuse (with the engine off) for 30 seconds. If the SES comes back on then it is time to go to autozone and have the codes scanned (free) and see what else is illuminating the icon.

Regards

Thanks for the information! Where is the PCM located on the Grand Am? I have had the codes scanned for the SES light, and it comes back with a failure code of P0113, which is Intake Air Temp Circuit High Input.

[01Z]

Originally Posted by aerial_22

Thanks for the information! Where is the PCM located on the Grand Am? I have had the codes scanned for the SES light, and it comes back with a failure code of P0113, which is Intake Air Temp Circuit High Input.

If all you want to do is clear the trouble codes and potentially turn out the light, you need to remove the fuse cover in the engine compartment. It can't be missed as it is domed oval with the word FUSES embossed on top. I'm going from memory because when the O2 sensor went bad the SES light remained on after replacement. Any way, I believe the fuse you want to pull is plainly marked. If not, you will need to refer to the owner's (or like haynes) manual.

If you really want to locate the ecm then I will have to go by memory as my son has taken the car with him to work. I'm thinking it is tucked up above the firewall on the passenger side. Look for a 12 x 8 x 3 inch rectangular aluminum box with short cooling ribs around the perimeter.

Regards

[01Z]

Originally Posted by aerial_22

I am having problems with my air intake temperature sensor on my 1999 Grand Am SE 3.4L. I have had it replaced, but my check engine light remains on. I am concerned when the sensor went bad that it shorted out the contact for this sensor on the car's main computer. Anyone had a similar experience?

Also, sometimes the obvious is overlooked. Make sure the little cable plugging into the intake plenum is seated in properly. Check the cable as far into the loom as you can. Look the connector over carefully for bent pins or distorted openings. If you want to give it a try, plug a 6k ohm resistor into the connector (on the cable) to verify that your pcm is seeing a good value. 6k should tell your computer that the ambient air temperature is about 65 - 70 degrees fahrenheit. I am unfamiliar with the 3.4L engine so you would be doing the resistor trick at risk.

Regards

[aerial_22]

Thanks again for the information! I am not sure clearing out the OBD code to turn my SES light off will be much help. After it goes through a full cycle I am sure that the light will come on again. I was reading another forum on OBD codes, and a member with a 1999 Alero with the same 3.4L engine was having a similar problem. They replaced the sensor, and after a short time the SES light came on again. At this point I may need a full diagnosis on the probelm, but the cost for the diagnosis is typically $90-120 just to tell me what the problem is.