Engine in Limp Home Mode, CEL and Wrench lights on?

[L_turn9]

Hi ya'll,
Had a bad Alternator so I installed a new one from Autozone, and while the engine started and ran great after the alt was installed, when my wife went to the store, the CEL came on, a few minutes later the Wrench appeared, then I believe it went into "Limp Home Mode" where it drove as long as the driving was moderate.
Maybe I knocked a hose loose when I installed the Alternator, I'll check shortly. I guess it's possible, but I looked around pretty closely, but it won't hurt to try another look before I take it to my Indy for a code check.

Thanks in advance for any suggestions.

Larry

 

[Explorer_PL]

It could be ABS tone ring, completely unrelated and pure coincidence.

Codes ???

 

[L_turn9]

Thanks for the suggestion, I've never heard of a ABS Tone Ring, I'll search for it, but maybe you could provide some additional info? Also, the problem we had where the ignition switch will not allow the key to be inserted happened again. Seems like lots of things are happening at once, maybe they're all un-related? After installing the new alternator, I cleared the codes and they were gone for a little while. I am still seeing O2 Sensor (all 4) and EGR valve codes so they'll be installed next week. problems, problems, problems.

 

[Explorer_PL]

At the end of each half shaft in the rear, there is a ring on the outer ends of them as they enter the knuckle. The ABS sensor receives the pulse signal from them. They tend to crack and disrupt the signal.

 

[L_turn9]

It's been a while since I last posted, so I'll bring ya'll up to date. Took it to a shop where I was told the O2 Sensors and MAF were all bad. Had those replaced and picked the truck up. It got 1/2 way home before the CEL and Wrench came on again. Took it to a different shop who kept it a week and found a broken MAF wire as well as a wire going to the ECU. Had those fixed and all was well for about a week - it drove better than it ever has. Then, Saturday my wife says she barely made it home. Once she gets let down by something like this she never trusts it again. I can see her point - she doesn't want to be 20 mi from home & have the engine stop. So we'll take it back tomorrow and see if they can find the problem this time. I believe it's another broken/loose wire somewhere but I can't work on it. I guess it's also possible there's a bad solder joint in the ECU or Ignition Switch. Anyway, maybe someone out there has had a similar problem? Hopefully it's not something that is affecting a lot of the 06 Explorers! Thx for listening -
Larry

 

[94Eddie]

I have read here about certain model years of 4th gen Explorers have bad insulation on the wires that deteriorate and short out over time. Maybe yours is one of them.

 

[explodermann256]

I have read here about certain model years of 4th gen Explorers have bad insulation on the wires that deteriorate and short out over time. Maybe yours is one of them.

This. This is a problem from late 06 to early 08 from what I gathered. My engine wiring harness is completely destroyed due to rotting insulation. My wrench lights and CEL illuminate out of nowhere occasionally, presumably due to this. When that happens, the truck goes into limp home mode and drives like the transmission is bad LOL. Turning the truck off and on will make the wrench go away and it will go back to normal for a while. The code that comes on when this happens is related to the throttle position sensor voltage even though I replaced the TPS three months ago along with the pigtail for the TPS. I'm guessing the wires are corroded even further back as well.

 

[explodermann256]

It's been a while since I last posted, so I'll bring ya'll up to date. Took it to a shop where I was told the O2 Sensors and MAF were all bad. Had those replaced and picked the truck up. It got 1/2 way home before the CEL and Wrench came on again. Took it to a different shop who kept it a week and found a broken MAF wire as well as a wire going to the ECU. Had those fixed and all was well for about a week - it drove better than it ever has. Then, Saturday my wife says she barely made it home. Once she gets let down by something like this she never trusts it again. I can see her point - she doesn't want to be 20 mi from home & have the engine stop. So we'll take it back tomorrow and see if they can find the problem this time. I believe it's another broken/loose wire somewhere but I can't work on it. I guess it's also possible there's a bad solder joint in the ECU or Ignition Switch. Anyway, maybe someone out there has had a similar problem? Hopefully it's not something that is affecting a lot of the 06 Explorers! Thx for listening -
Larry

Sounds exactly like whats happening with mine. Wires leading up to the MAF (and numerous other connectors) were rotting away. It would stall at random as well. When I replaced the pigtail harness leading up to the MAF it was running better than ever. Shortly after, back to the same old, minus the stalling. Wrench and CEL, rough idle, etc etc. I traced the wires further back only to find that where the wires from the MAF meet the main harness above the passenger side fuel rail is a complete mess. The wires are all almost bare from rotted insulation and all touching. Ugh. Ford was using piss poor wiring insulation on these trucks from about late 06 to early 08. If I were you I would get a complete engine wiring harness. I'm going to be doing so in the near future myself. If its used make sure it isn't butchered or cracking like ours.

 

[Explorer_PL]

I tried to get e new harness for my 06, they are discontinued. Dealers don't have it.

Junk yards ????

 

[L_turn9]

Thanks Gang, Yeah, I could definitely agree that it might be the wiring insulation crumbling! I have owned several old Mercedes' and back in the 90s/00's they started using "Biodegradable" insulation. Some kind of green movement that started in Europe and nw we're paying for it. I think whatever nitwit thought that brilliant idea up should be hung from a flagpole! Why would the gov't mandate older cars - (which are all some of us can afford) - start to fall apart at X years after production! But I guess that would be typical for someone in the friggin' government. Evidently someone in the US thought wiring that falls apart on command would be a good idea? Probably a socialist who would prefer we are all walking...
Thanks again for the thoughts - it's back in the shop - not a F dealer because I think they would say all the aftermarket parts I had installed are the problem and they'd want to replace them with FoMoCo parts. But I seem to be ranting. Sorry.
Hopefully my Indy can fix it this time! Thanks for the comments. BTW, when we bought the truck a PO, had removed the Nav System/Stereo and installed an aftermarket stereo. It's been years since I spent any time behind a dash putting a radio in, and I know some people start looking for hot leads and Ground points, and sometimes they tap into the wrong wire. Are there any Power & Control Wires in the vicinity of the stereo head unit? All the Nav stuff is gone and there's only a Alpine CD player where the Nav/Stereo was. I always worry about someone grabbing a power lead going to the Ignition and screwing things up.
Thanks

 

[L_turn9]

I tried to get e new harness for my 06, they are discontinued. Dealers don't have it.

Junk yards ????

Good thought but I'd be fearful I was installing another wiring harness that was self-destructing.
Thanks
Larry