LT1Jeepin

I have a 95 caprice motor and the check engine light came on and the engine started to cough and sputter then it cleared up and the light went off. Then the next day nothing happened. Next time I drove it it done it again. I took it in and got the code read and it gave me a DTC48 which is the MAF sensor. I ran to the junkyard and grabbed another sensor to try. Problem still there. Thought I'd try a new one just in case. Put it in and the check engine light came on and it kicked the fan on immediately. Not good. Still the same code. Drives better now that the MAF isn't working though. Must have been going out for some time and that was killing my mileage. So what I'm looking for is the correct way to diagnose this problem. On the plug there is a black, pink, and yellow wire. I'm assuming that one is a signal wire and one is a voltage and one is a ground? I may not be correct on that but if someone could give me a hand on this I'd surely appreciate it.

shoebox

First thing to do is check for 12v power on the pink wire when the key is ON.

LT1Jeepin

Thank you sir. And is that the "usual" problem by chance?

shoebox

That would be why I mentioned it, yes.

LT1Jeepin

Ok. Finally got around to checking the plug on the MAF. On the pink wire I'm looking at 11.5 volts with the key on. On the yellow wire I'm looking at 5.0 volts. That seems like it should be working correctly shouldn't it? Please help me out. Think I just got a bum MAF from the parts store?

shoebox

I would monitor MAF activity with a scanner.

LT1Jeepin

Tried to clear the code and it shows right back up. I'll take it and put it back on the scanner again. And I'll post up what I find out. Thanks

Guest47904

If there is no ground on the black wire, you will get the same code. When you measured your 2 voltages, did you check it to the black wire or to another ground?

LT1Jeepin

Checked it to another ground (battery). I'll double check that wire just to make sure it's grounded good. Thanks.

LT1Jeepin

Speedygonzales- You were on target man. Thanks. Ended up being a broken ground wire coming from the harness right below the computer. Glad it was an easy fix. I got tired of looking at my "self destruct" MIL light. THanks for all the help guys.

LT1Jeepin

Ok, So I thought I had it fixed. I put another MAF on it jsut to make sure that it wasn't the problem when I fixed the ground wire. Well it ran well until I got on the interstate. Started pulling at about 65-70 and it just gave a hard jerk. No MIL light. Started to do it more frequently. Then the MIL light came on and it cleared up and went off. The next day it done it again. Started to kinda put a little load onthe motor and it got worse. Once the MIL light came on and stayed on it has cleared up and will run up to 6 grand with no problems. What would cause the MAF to be dying like that? I will say that it is not a new MAF, it is a reman. I wouldn't suspect that it would be the case but anymore you never know. Let me know what you guys think.

Guest47904

I wouldn't assume it's the MAF until you get the code.

LT1Jeepin

I'm just going by the way it acted this time compared to the time before. Did the exact same thing. When that happened, that was the code that was in the computer. I'll get it checked and see what it is, but still I'm leaning towards the MAF.