Service Engine Soon Light with codes (Replace IAT Sensor Connector) #02-06-03-005

[iceman]

Service Engine Soon Light With Stored Codes P0112, P0113, P1111 or P1112 (Replace IAT Sensor Connector)
1997-2002 Chevrolet Malibu

1997-1999 Oldsmobile Cutlass

1999-2002 Oldsmobile Alero

1999-2002 Pontiac Grand Am

with 3.1L or 3.4L Engine (VINs M, J, E -- RPOs L82, LG8 , LA1)

Condition
Some customers may comment that the service engine soon light is on.

The TECH 2 will show stored diagnostic trouble codes P0112, P0113, P1111, or P1112.

Cause
This condition may be caused by a broken wire at the intake air temperature (IAT ) sensor connector. The break may not be readily apparent as the insulation may be intact.

Correction
If routine diagnosis leads to a broken wire at the IAT sensor connector, replace the connector as follows:

Remove the tape from the engine harness convoluted tube where the IAT circuit wires join the main engine harness.
Locate/isolate the 2 IAT wires within the engine harness.
Disconnect the IAT connector from the IAT sensor.
Remove the tape from the IAT and MAF (mass air flow) sensor wires to allow removal of the IAT wires.

Important
Before cutting the IAT circuit wires, it will be necessary to determine the proper length. You need to add 38 mm - 50 mm (1.5 in - 2.0 in) to the length of the wire going to the IAT. Also, when cutting the IAT circuit wires, it is important that the wires are cut in a manner that will not create a large mass. Stagger the cuts and install the connector kit. Original connector cavity "A" has a red wire and cavity "B" has a tan wire. Make sure cavity "A" and cavity "B" wires on the replacement pig tail connector match "A" and "B" wires on the engine harness. This will provide strain relief and prevent recurrence of this concern.


After staggered cuts are made on the IAT wires in the engine harness, strip a small amount of the insulation from both wires and install the kit butt connectors to the bare IAT wires by crimping both.
Stagger the cuts on the pig tail wires to match the IAT engine harness wires.
Strip a small amount of the insulation from the pig tail IAT wire ends. Install and crimp both wires into the open end of the butt connectors that were installed on the engine harness IAT wires.
Heat shrink both IAT butt connectors and let the wires cool off.
After cool down is completed, the harness can be neatly taped with electrical tape.
Install the IAT connector on the IAT sensor.
Clear the codes.


Parts Information
Part Number
Description
Qty

12102620
Connector Pig Tail
1

[2000gagt]

Could you please tell me where the IAT sensor is located. I don't think I have a broken wire, based on the fact my SES light goes on and off every few days. I am thinking bad sensor. Thanks

[iceman]

There is a black "ribbed" plastic tube that goes from the throttle body to the airbox/maf.. The IAT sticks right in the middle of that black tube.

[swordfencer]

When this happened to me, my transmission begin to shift very hard. It did this while running as well as putting it into drive from park.

It turns out the IAT sensor shares the same 5V reference voltage with the coolant sensor and the TPS. When the IAT sensor connector went bad, it messed up the TPS. The computer then upped the transmission pressure to protect the transmission. (thanks to Spoon for the is information!)

[iceman]

I'm dumb, what exactly is the higher pressure protecting??

Also good info about the 5v reference voltage being shared

[swordfencer]

Same here, I do not know why the computer kicked up the transmission pressure to protect the transmission. Would have to ask Spoon about that one.

Hopefully this helps out anybody who has similiar symptoms. My SES light did not come on right away. It started to shift hard, then I turned the car off, came back to it an hour later, turned it back on, shifted hard when I put it into park. Then I drove off, and about a mile later the SES light came on, but then the hard shifting stopped.

[brdrxtreme]

I am having the same problem with my grandam.......shifting hard......trac off light is on, and so is the service engine soon light. i have already replaced the iat once...which is also called the air charge sensor right??? the code that it is throwing is a po113b IAT sensor circuit voltage.... does that meani have a bad wire or a bad sensor??? i have no clue.

[brdrxtreme]

the code says "iat sensor circuit voltage high"

[swordfencer]

When the dealer did mine, they replaced the connector to the sensor. From what I got from Spoon, the IAT, the TPS, and the coolant temp sensor all share the same reference voltage. So if the IAT is high, it could be causing the TPS to malfunction.

I do not know if the intake air temp sensor is the same as the air charge sensor. You can try replacing the connector to the sensor and see if that works. For some reason, the connector goes bad and it grounds out or shorts out.

[brdrxtreme]

how much did they charge u do replace the connector?

[swordfencer]

I got it replaced under warranty. It took them under an hour to do. I really do not know how much it would have cost otherwise, but it should not be more than $75-$100.

[brdrxtreme]

air charge sensor i replaced a month ago went bad.........car runnin great again!

[shark2000]

I am checking the resistance on the temp sensor. What is the correct reading I should get? I have the hard shift, but I tested the wires with an ohm meter (ohm eater) and it shows fine. The sensor tests @ 3.3 ohms.

[Silver02GT]

Whoa...talk about a post brought back from the dead...

[shark2000]

Warrenty ran out a week and a half ago. Now this happens.

[shark2000]

Just messing with the wires and checking it and putting it back together, it's now working normal. It also caused my head lights (not daylight running lights) to come on with the sun out for about 3-4 minutes. Everything’s working now.

[chavezgt]

Well, I've replaced BOTH the IAT sensor, and the connector, but it keeps throwing the P0113 code. Any thoughts? Could it be that I have to use a certified "GM" sensor vs. the one I got at Autozone? I'm a little miffed/confused, seeing as how my car runs just fine. Bah!

[chavezgt]

Update:

Replaced IAT sensor with AC Delco sensor. SES went out for about 15 mins, and now it's back on. Ungh.