Intake Air Temperature Sensor

[cgholson]

I have a 91 LS 400 which I recently replaced the oxygen sensor on the right side before the converter. I car is still stalling on me and a code has come back now that the trouble area is the intake air temperature sensor saying there's a short or opening in the circuit wire. Where is this located at on my car so that I can look at it to see if there's a problem with it.

[VBdenny]

What I would do would be run the car up on ramps and do a visual inspection. Since you just had the oxygen sensor replaced and it failed shorty there after, I would suspect that some of the wires might have been pushed against an exhaust manifold and burned through, thus the open circuit.

Doesn't cost a thing to look and it (hopefully) will be a quick fix. Good luck and all.

[cgholson]

What I would do would be run the car up on ramps and do a visual inspection. Since you just had the oxygen sensor replaced and it failed shorty there after, I would suspect that some of the wires might have been pushed against an exhaust manifold and burned through, thus the open circuit.

Doesn't cost a thing to look and it (hopefully) will be a quick fix. Good luck and all.

Thanks for the response. I haven't gotten anyone to do this yet. Besides this is there anything else it might be and the temperature sensor is located near the exhaust manifold?

[wwest]

What I would do would be run the car up on ramps and do a visual inspection. Since you just had the oxygen sensor replaced and it failed shorty there after, I would suspect that some of the wires might have been pushed against an exhaust manifold and burned through, thus the open circuit.

Doesn't cost a thing to look and it (hopefully) will be a quick fix. Good luck and all.

Thanks for the response. I haven't gotten anyone to do this yet. Besides this is there anything else it might be and the temperature sensor is located near the exhaust manifold?

If your LS has an intake air temperatrue sensor it will be in the engine air intake assembly just downstream of the intake air filter.

[cgholson]

What I would do would be run the car up on ramps and do a visual inspection. Since you just had the oxygen sensor replaced and it failed shorty there after, I would suspect that some of the wires might have been pushed against an exhaust manifold and burned through, thus the open circuit.

Doesn't cost a thing to look and it (hopefully) will be a quick fix. Good luck and all.

Thanks for the response. I haven't gotten anyone to do this yet. Besides this is there anything else it might be and the temperature sensor is located near the exhaust manifold?

If your LS has an intake air temperatrue sensor it will be in the engine air intake assembly just downstream of the intake air filter.

Excuse me for asking but not all 91 ls 400's have an intake air temperature sensor and when you say downstream of the intake air filter are you simply referring to the air filter?

[wwest]

What I would do would be run the car up on ramps and do a visual inspection. Since you just had the oxygen sensor replaced and it failed shorty there after, I would suspect that some of the wires might have been pushed against an exhaust manifold and burned through, thus the open circuit.

Doesn't cost a thing to look and it (hopefully) will be a quick fix. Good luck and all.

Thanks for the response. I haven't gotten anyone to do this yet. Besides this is there anything else it might be and the temperature sensor is located near the exhaust manifold?

If your LS has an intake air temperatrue sensor it will be in the engine air intake assembly just downstream of the intake air filter.

Excuse me for asking but not all 91 ls 400's have an intake air temperature sensor and when you say downstream of the intake air filter are you simply referring to the air filter?

Someone correct me if this is wrong but I don't think the early LSes had an IAT. If a "hot wire" MAF sensor is used then an IAT is required to correct the mAF signal. I'm pretty sure my 92 uses some sort of mechanical rotation or vane sensor that is deflected by incoming airflow rate. And yes, the electrical connector on the top of the duct/pipe/tube leading away from the engine intake air filter housing is the connection for the MAF.

[cgholson]

What I would do would be run the car up on ramps and do a visual inspection. Since you just had the oxygen sensor replaced and it failed shorty there after, I would suspect that some of the wires might have been pushed against an exhaust manifold and burned through, thus the open circuit.

Doesn't cost a thing to look and it (hopefully) will be a quick fix. Good luck and all.

HI VBdenny,

I finally did what you said today and put my car up on some ramps and the wires at exposed at the end where the sensor plugs in and also you the connection end. Can I repair these exposed wires or do I need to buy a new sensor?

[cgholson]

What I would do would be run the car up on ramps and do a visual inspection. Since you just had the oxygen sensor replaced and it failed shorty there after, I would suspect that some of the wires might have been pushed against an exhaust manifold and burned through, thus the open circuit.

Doesn't cost a thing to look and it (hopefully) will be a quick fix. Good luck and all.

HI VBdenny,

I finally did what you said today and put my car up on some ramps and the wires at exposed at the end where the sensor plugs in and also you the connection end. Can I repair these exposed wires or do I need to buy a new sensor?

Can anyone answer this question for me. It's been a few days and I can't believe of the lexus owners I'm the only one that's had this problem????

[glenmore]

So the car was stalling, you read the code, it indicated o2 sensor and you replaced the o2 and nothing has changed? Then after you changed the o2 sensor you got another code for the air intake temp sensor?

I just had a problem with my air flow meter. I believe I sprayed it too heavily with a MAS cleaner and this caused a low RPM stalling condition. Complicating matters is that I had just done the plugs, caps, rotors and wires and it is usually a good bet to review your most recent work if something is not right. I would start the car. It would idle perfectly at 1000 in the warm up stage. Then after a minute or so, RPMs would drop to the normal 500 and then jump around and stall. After checking my work, the stalling was still there but happened after more idling. The next day I drove the car and no stalling. I am theorizing that my air flow meter finally dried out. I took the car (no stalling) to my indie and he pulled a fault code for the air flow meter AND the air temperature sensor and he asked if I had started the car without it plugged in, and indeed I had. He reset it and all is fine. He said that both sensors are in the same part, a black rectangular box attached to the aluminum housing just inboard of the air filter. Work very carefully around this unit. It is VERY expensive to replace. My indie told me to never spray any cleaner on a Japanese air flow meter, that they are a different animal than the typical US air flow meter/ mass air sensor.

A cursory look for this part came back with the entire unit, the whole plastic piece with steel honeycomb, black box and aluminum housing and attached bellows but ebay has just the important part.

This is what mine looks like:

http://cgi.ebay.com/ebaymotors/Lexus-LS400...emZ230272287976

http://cgi.ebay.com/ebaymotors/LEXUS-LS400...emZ110270571690

glenmore

1990 LS400

1991 300CE

2000 C280