1992 Lumina 3.1 Engine code 23

[Hwilli1647545487]

Well since we are muddling up the tech section with lot's of GM 3.1 Liter questions, I figured I would add my own.

 

This is my fiancee's car, recently transfered into my name for insurance purposes. Wouldn't you know it as soon as it's mine shit starts to break.

 

First it's leaking oil (fuck it add more)

 

Then the steering feels really sloppy (probably doing this for awhile). Found part of the problem is the PS mounting bushing for the steering rack. Not 100% of the issue, but certainly part of it. Will investigate more this weekend.

 

Then last night at 5:30am she is driving to work, and the temp needle starts bouncing between middle, and pegged. She calls me on the cell. I tell her to drive it home, I leave work to take her to work.

 

Swapped the thermostat, and bled the coolant system. It seems fine now, but we'll see in the weeks ot come as it gets driven more.

 

Finally I decided to pull the codes on it (it has a service engine light on for awhile) since I was out there dicking with it. I get a code 23. Sadly I have been up for quite some time, and I don't have the book in front of me now... so my wording won't be exact.

 

I believe it was a manifold temp sensor. Low temp error. Anyone know where this sensor is located, and how to test it. If its not an important sensor (doesn't sound like it and the car runs fine). It will be another "fuck it" She is getting a new car in Spring anyway.

 

Anyway Had to vent a little with my question.

 

TIA,

 

Howard

[Lustalbert]

its telling you to replace the engine.

[Hwilli1647545487]

Originally posted by Lustalbert:

its telling you to replace the engine.

No, it knows I hate it, and now that it's my responsiblity, it's making me pay.

[Rotarded1647545491]

CODE 23

 

Trouble Code 23 indicates that the Manifold Air Temperature sensor is reporting abnormally low readings. When the air is cold, the thermistor in the sensor has a high resistance, which falls as the air charge warms. Low readings thus indicate a possible bad sensor or open in the MAT circuit.

The conditions for setting this code are:

• MAT reading is < -40 deg F NOTE: A default MAT value indicating 82 deg F is used while Code 23 is present.

Typical thermistor resistance values are:

deg F deg C resistance in ohms

210 100 185

160 70 450

100 38 1,800

70 20 3,400

40 4 7,500

20 -7 13,500

0 -18 25,000

-40 -40 100,000+

 

 

Typical causes for this code include:

1) Defective MAT sensor

2) Open sensor ground circuit

3) Dirty or corroded connection at MAT and/or ECM

4) Open circuit between the ECM and the MAT sensor

5) Defective ECM

[Hwilli1647545487]

Thanks, That's a start.

 

 

Now does anyone know where the MAT sensor is located at on this particular motor?

[nurkvinny]

From a GM repair forum:

 

The MAT (manifold air temperature) sensor is located to the rear of the intake manifold slightly to the left. (Driver’s side)

[nurkvinny]

More from the web :

 

Most of the time I see this code the sensor is unplugged. But I have done some wiring repairs also for this problem.

If the sensor is reading a very strange number like -40 degrees than the computer is seeing an open circuit and defaulting to the negative number. If you jumper the 2 wires together the sensor reading should go high! If it does than you have a bad sensor if not you have a broken wire.

....................

[Hwilli1647545487]

thanks much!

[Doug1647545489]

Pull off the sensor. Stick a 3400 ohm resister in where the sensor plugs into, reset the computer. See if it goes away, leave the resister in there and wRAP it in e-tape or something. Problem solved. The car will just think its 70 deg all the time.