For months I have been trying to diagnose why I am getting a P0100 and accompanying rough idle. For those of you that had a P0100 with a short/blown fuse, how did you get it resolved? What was the culprit?

After a search on the board, I found many threads pointing to the MAF wiring or pigtail as a common source on 97s. Some times I get just the P0100 and sometimes I get P0100 with PO1657 and PO1667. When these additional DTCs appear the 20 amp Engine Sensor fuse is generally blown. This suggests I have a short somewhere.

I bought a new MAF pigtail to replace the oem one. But before I dig into to my oem wiring harness (that I am reluctant to do unless really necessary) is the MAF wiring the problem? Could the problem be from other components on the same circuit, namely the O2 sensors, the Reverse lock out solenoid or Shift solenoid or something called a TCC?

You might answer that I should test each, but I am not sure how I would go about doing that. If I need to rule out the other components mentioned above, can you provide the steps on how I should do that? BTW, I bought a nice test meter to address this problem, but I am a little inexperienced using it. Any help would be appreciated.

 

It's more likely a short to ground at the wiring for one of the other devices on the circuit and not the device it self. Just inspect the wiring going to all the devices on the same circuit. If at that time you don't find a wiring issue, start pulling the wires off one device at a time to see what doesn't cause the fuse to blow when it's unplugged.

 

Hey, Speedy, thanks for the reply. I'll do a visual on some of the related circuit component wiring, to the extent that I can follow it. That makes sense.

But is there any particular reason you believe the short is not associated with the MAF wiring? I mean, most of the posts I read during my search on the P0100 suggested a MAF related wiring problem. One actually referred to a similar problem I am having and involved a short, but there were no other follow-up posts on that thread. Just wondering.

Lastly, I guess I will need to follow the process you mentioned regarding disconnecting some of the other items on the circuit such as the O2s, as there is a chance one of those lines could be subject to conditions that would lead to a short.

Boy, this testing process is going to take some time.

 

I incorrectly (apparently) assumed you already looked over the wiring for the MAF. As you know, the MAF, all 4 O2 heater circuits, the reverse lockout sol and the skip shift solenoid are all on the same 20 amp fuse in the U/H fuse panel.

Don't forget the splice in the harness (S104) where it branches off to all the devices. It is located near the break out of the main engine harness to the transmission.

 

Well, yes, I gave it the once over with my eyeballs, but nothing appeared faulty.

I will check the harness as you suggested. I'm also going to try to examine the O2 sensor wiring this weekend when I have time to jack the car up and do some occular analysis. I am not experienced tracking down wiring problems. I just hope I find something obviously wrong and am able to get the car running well again soon.