Hi,

I'm new to the forum and glad to be a part of you guys. I have a 1984 Sedan Deville. I have taken a reading on the computer and I get two codes. Code 13 (O2 Sensor Not Ready) which I know what that is, and 38. I'm concerned with the 38 meaning "Open Mat Sensor Circuit". It seems to be an electrical problem, but can anyone tell me what this means and what does it take to fix this problem. Thanks!

Caddman

The MAT is the manifold air temp sensor. The problem is these can be well hidden because they are small sensors and are only 2 wires. I do not know where yours is located though. I'm guessing the engine is the HT4100 FWD right?

1984 was still rear wheel drive.

The MAT is the manifold air temp sensor. The problem is these can be well hidden because they are small sensors and are only 2 wires. I do not know where yours is located though. I'm guessing the engine is the HT4100 FWD right?


I'm not sure Dave. It is a 84 and it does have rear wheel drive. Is this a problem and is it simple and inexpensive to troubleshoot or fix. Another thing is my lights are acting weird. The low beams will just go out and I have to cut on the high beams and that just upsets people heading toward me. Thanks for getting back.

1984 was still rear wheel drive.
That's correct it is rear wheel drive. Do you have any idea on how to fix the code 38 and some ideas on how I can fix it inexpensively? Thanks Brougham.

The MAT is not too hard to troubleshoot or fix if you know what you are looking for. Look for a sensor with 2 wires coming out of it on the manifold. Once you find it, just check the wires for any damage. If theres nothing ovbious, i'll look up the diagnostics procedure when I get back in shop. With the headlights, check the dimmer switch, it's located on the steering column under the dash. Just keep clicking away while you look underneath for whatever moves with each click. Make sure the connectors are plugged in fully.