Help Check Engine Light!

[BadAzzexplr]

hi, I have 1997 Ford Explorer AWD V8 5.0. My check engine light has come on, but the truck is running fine. I had the codes scanned and it came back with "abnormal air intake temp". I checked my air filter and it needed replacement.

I cleared the code and it came back again. I changed the air filter and made sure the surroundings were clean and then disconnected the battery for 20mins to clear the codes. I then drove it for like 10 miles and no check engine light.

Later I started it and as soon as I let it idle for about a minute it came on again and would not shut off.

I was going to attempt to clean the Mass airflow sensor, but a little concerned about taking it a part. Has anyone got any ideas or other things I can try.

 

[Jason_25]

Don't clean the MAF. Clean the IAT. It's located upstream of the MAF.

 

[BadAzzexplr]

is that the sensor that is between the mas & the box. It looks like a temp sensor that fits in the hose? If so what do u clean it with?


Thanks

 

[Jason_25]

Yes that's it.

Just clean it with any old intake cleaner or throttle body cleaner.

 

[Robert]

I doubt if cleaning it will help though. It could be caked with dirt or mud and it will still read somewhat normal temperatures. Anything within a normal range of around -20F to 200F would be considered normal. If the sensor fails it will either lock to the bottom or top of its range depending on the type of sensor and the type of failure. On the RTDs we use at work, when they open up they lock in to about 932F. If your computer is seeing something that extreme it will set a code. Get a scanner and monitor the IAT to see what temperature it is putting out. If it is in a somewhat normal range then try wiggleing the sensor around while watching the temperature. If you see it jump or spike then either the wiring leading to is bad, the connector is bad or the sensor is bad. It will probably be the sensor unless you strained the wire when you replaced your air filter. If you don't have access to a scanner to run some troubleshooting steps then it would be much cheaper to just buy a new IAT sensor as opposed to a scanner that will run the tests. My scanner runs about $350 and will do the tests. The IAT should be less than $100, probably much less.

 

[mosinman]

IAT sensor. Cleaning almost certainly wont help unless it is so grunged up to be unrecognizable. Buy a new one. The IAT sensor helps fine-tune the fuel/air mixture for optimal fuel economy and performance. IAT sensor failure in and of itself may not cause your engine to run rough, just not optimally.

 

[BadAzzexplr]

I cleaned the IAF and also took apart the throttle body and cleaned it as well. The same thing happened, I drove it for like 10 mins and then as soon as I started the second time the light came on at idle and would not shut off.

The wires look good on the sensor, I am gonna have the code scanned once more and see if there is more than one code, otherwise my next step is to replace the sensor. Has anyone experinced this before.


Thanks for all your replies!

 

[Jason_25]

What is the IAF?

 

[BadAzzexplr]

My bad! Its the IAT.

 

[explorer4x493]

I have the exact same problem with the check engine light. I dont know what to do. I have had the darn the scanned too many times and every time it goes off for a couple of minutes and then when i give it alot of gas it just pops back on. what do i do?? help it's making me about go to the point of taking out the bulb and just leaving it at that... Thanks to anybody that responds...

 

[aldive]

What trouble sodes are beong shown?

 

[BadAzzexplr]

Ok, I replaced the IAT sensor. No luck Check Engine comes back on after resetting the code. I checked the wires and they seem fine. Any ideas. Here is the code I am getting.



Diagnostic Trouble Code (DTC) P0112
DTC Definition: Intake Air Temp Circuit Low Input

 

[finn_jacob]

my check engine lights comes on all the time...i took it the first couple times but there is nothing wrong at all....if you take in and it is ok and soon after the light comes back it is probably nothing to worry about....sometimes mine stays on for a day or two an then the light goes out but nothing is actually wrong...i wouldn't worry too much

 

[BadAzzexplr]

Also is there a ground for this sensor and if so where is it located. I checked the another website for codes and it listed possibly problems associated with that code


Possibly Problems
- Grounded Cirucit in Harness ( how do I find out this)
- Improper Harness Connection
- Damaged Sensor (replaced)
- Damaged PCM

I apprecaite everyones help. Thanks.

 

[finn_jacob]

i am pretty sure it is due to improper harness connection...the light comes on when i hit a bump lets say and on the the next bump the light goes off..i have gotten used to the light and am too lazy to check the wiring, but that is most likely the problem

 

[Crankcase]

Just try shaking the harnesses by hand while the truck is running. The light will flick when you find the bad harness. Easy.

 

[BadAzzexplr]

This seems to be a hard code in the system and it won'
t flicker on and off. Once the CEL is on, it won;t shut off till you clear the code. Where is the ground for the harnesss and where does the harness come froM?

 

[Robert]

Have you gotten a chance to monitor the IAT temperature both while driving and sitting still? What does it read? Besides looking for obvious wiring problems, that information would be helpful. It would be good to know if the temperature starts off reading correctly and then some particular instance causes it to flake out. I have never traced the harness back to its origin, but I do believe it goes down past the alternator into a much larger harness down by the fender. It will be covered completely in black tape and probably won't be visibly obvious if there is a break in the wire. I do not know where it gets its ground from, but it has to be through the one of the wires going to the sensor since the sensor is inserted in to the rubber intake hose. That would prevent the sensor from grounding through itself.

 

[Robert]

Another quick test would be to follow the IAT wires back as far as you can and measure the continuity from that point to the connector. It may be something as simple as a bad connector.

 

[BadAzzexplr]

I am almost positive its the clip that plugs into the sensor. Where can I get another clip to replace the plug? Ford will not sell just the plug they want to sell the whole harness.

also, in the sensor is working do the codes still need to be reset or should they go out after the problem is fixed?