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View Full Version : Need Help Finding O2 Sensor Fuse



champ1173
07-11-2014, 04:01 PM
I had my motor rebuilt a couple of months ago, and about 20 mins after I picked it up, the CEL came on. I would've taken it back to them, but that's another story. Anyways, the codes I got were, P0135, and P2195. I cleared them, and they kept coming back. So I had a shop put a new O2 sensor in. Again, about 20 mins later, the CEL came back on. Come to find out, by reading different posts here, that the wrong O2 sensor was put in. Needless to say, I bought the Motorcraft one from Rockauto, and they put it in for free today. This time, the CEL only took 10 mins to come on. I pulled over and checked it, and sure enough, P0135 was staring me in the face, AGAIN! Well, after reading all the symptoms for this code, it says I have to check connectors, which was done, and check the fuse. Anyone know where the fuse is located? I already googled it, and the closest I could find, was a 2000 CVPI. Well, the location it's in says, not used, on our cars, in the owners manual. Though it said it's a 15, so that kinda narrows down my search a lil. Any help would be appreciated.

ctrlraven
07-11-2014, 04:45 PM
Do you have headers?

Which O2 sensors were replaced, upstream or downstream?

Is your tune stock or tuned by someone?

ctrlraven
07-11-2014, 04:56 PM
P2195 is the front passenger side O2 sensor, if it was replaced with something other than Bosch, NGK or Motorcraft it could cause an issue. Also O2 sensors should be replaced in pairs on cars where there is.

Bank 1 is passenger side
Bank 2 is driver side
Sensor 1 is front (Green Plug)
Sensor 2 is back (Blue Plug)

I see you had this issue for a month now http://www.mercurymarauder.net/forums/showthread.php?t=93724

Zack
07-11-2014, 04:56 PM
Wiring problem brah.
Check the main harness plug first

ctrlraven
07-11-2014, 05:00 PM
Wiring problem brah.
Check the main harness plug first
That would be my guess also, something might have been pinched or shorted out during the removal/install the motor.

champ1173
07-11-2014, 05:59 PM
Do you have headers?

Which O2 sensors were replaced, upstream or downstream?

Is your tune stock or tuned by someone?

I don't have headers. Bank 1 Sensor 1 (Upper passenger) was replaced. I have a tune from Mo. Oh, and yes, I've had this problem for about a month. The P2195 is gone now, probably because I have the right O2 sensor in there now. Here's another question I'm gonna throw at ya. Mechanic who did the O2 sensor said he scanned the codes, with his mega scanner, (My words, not his.) and 2 other codes came up, that I didn't get on my scanner. (Though I didn't check them on the SCT.) They were for the knock sensors. (P0325, and P0330) Now, are these turned off by the tune? Do I need to get new ones? Or, this is an electrical problem, that you and Zack are talking about? So I should probably have the other upper 02 sensor changed too?

champ1173
07-11-2014, 06:04 PM
Wiring problem brah.
Check the main harness plug first
You're probably right. The mechanic who put the 02 sensor in said the same thing. I'm no electrical genius, so this may sound stupid, but which one is the main harness? I'm honestly afraid to bring it somewhere, where they can rape me for taking a look at it, and fixin it. Something tells me, something like this wont be cheap either!

vegasmarauder
07-11-2014, 07:51 PM
Look for damage to the engine harness from chaffing or crushing at the back of the heads. When pulling engines, sometimes they crush the harness across the back of the engine and damage the wires. The passenger O2 sensor wiring runs thru this harness. It all plugs into a giant plug under the master cylinder. This plug has a bolt in the center. I have seen some where they forgot to tighten the bolt all the way.

champ1173
07-11-2014, 08:31 PM
Look for damage to the engine harness from chaffing or crushing at the back of the heads. When pulling engines, sometimes they crush the harness across the back of the engine and damage the wires. The passenger O2 sensor wiring runs thru this harness. It all plugs into a giant plug under the master cylinder. This plug has a bolt in the center. I have seen some where they forgot to tighten the bolt all the way.

There's a bolt there? I actually unhooked that harness, because it wasn't clipped onto the master cylinder. I'll take a look at those wires, and bolt 2maro. Thanks for giving me some kind of direction to go in. Actually, I unhooked the gray harness, but I see in a pic of my engine the harness with the bolt, that you're talking about.

champ1173
07-12-2014, 02:20 PM
So today I checked out that bolt on the harness, and it was tight. Though the wiring seemed to be kinda stuck between the cam cover, and the master cylinder. I wiggled it some, and was able to get it loose. There's a good possibility that one, or more wires were pinched in there. I'm really hoping that does the trick. One of the next things I'm gonna do, is go over the wiring for the MAF. There are 2 wires, that have a thicker gauge wire, woven in. I just gonna go to the junkyard, and cut off the wiring low, and splice them together. Having the same wire, and current, I would think would be better. Plus it would make it look cleaner. Fingers crossed, on breaking that harness free, and no more codes.