Issue with dtc codes

***Jackpine*** · #1 Mon, December 29th, 2008, 07:26 PM

Well heck, I hate it when I can't be brilliant! :cry:

Again though, the failsafe mode is only "real" when the engine overheats. For some stupid reason then, I'd have to say it got a false "hot" signal from the CHT sensor. (This shuts down fuel injection and possibly spark on every other cylinder - but air is still brought in to cool things down).

Since the engine was clearly NOT hot, it had to be a false signal, and, I suppose it's possible for CHT sensors to fail suddenly, and maybe to the HOT status, but I'd think it unlikely. I'd also be surprised to see that code go away just because you reprogrammed the PCM to Level 0, if the sensor was bad.

I'll be most interested in learning what happens when you return the tune you had before. I am absolutely positive a tune cannot cause this failsafe symptom! (And if it turns out it can, I'll never give anyone advice again). :sniffle:

(I meant to add - If you continue to have trouble on the Level 2 tune, post your problem in the "Help - Emergency" forum. I think Bill would want to know about it right away! And, I suspect he monitors that forum pretty closely).

- Jack

jerodr · #2 Mon, December 29th, 2008, 10:04 PM

Well...I programmed everything back to level 2 and went out and ran some errands and everything seemed ok. When I got home I checked the dtc codes and there were none so everything "seems" to be back in order. I'll keep driving it and hope that everything goes ok...not really sure what happened. Thanks Jack for your help.

Jerod

***Jackpine*** · #3 Mon, December 29th, 2008, 11:06 PM

Yea, well - I'm really glad to hear you weren't blown up or anything following my half-baked advice!

Honestly, I'm not an "expert" on these things at all, but, I DO read and I try to apply what I've learned in engineering to these problems. I also never advise anyone to try anything I wouldn't try myself.

But, now I have to tell you a tiny story about how I decided something in a single-lens reflex camera I had many years ago needed cleaning. It actually did need this treatment, but in the process, I totally ruined the semi-transparent mirror this particular Canon camera had. Bottom line was a fairly large repair bill to Canon to fix my fix! :o

So, I try to reason things out correctly - but, I'm afraid I get things wrong all the time!

And, I suspect when Bill gets a free moment or two, he'll inject his usual brilliance here to tell us what REALLY happened!

(AND - HE DID! So, did you "cold start" and slam it quickly into gear? I can't help but wonder though, why this action would put it into failsafe???)

- Jack

***Power Hungry*** · #4 Mon, December 29th, 2008, 11:16 PM

Jack,

You're second guessing yourself again. Don't do that. Trying to diagnose a vehicle problem over the internet is like trying trying to guess what I have in my fridge by me telling you I have food in it. Heck, Ford mechanics have the luxury of having the vehicle in right in front of them and they still get confused. Nobody can fault you for being wrong.

As long as you're honest, you can't go wrong.

There are specific situations where a failsafe mode could be the result of a bad calibration, but they have to a fairly specific set of circumstances. Not a big deal though.

I just came across that TSB yesterday and it is probably responsible for more than a few P2106 codes.

Don't sweat it buddy... Your doing a great job keeping the natives informed and happy.

Take care.

***Jackpine*** · #5 Mon, December 29th, 2008, 11:30 PM

Thanks, Bill - appreciate the kind thoughts. Actually, I wasn't too worried about the advice I was giving here, because I didn't think it could hurt anything. But, it's really interesting that failsafe can be activated through something other than high engine temps and, that there is a possibility that a programming error can cause it. (Although, on second thought, I can see how it would be easy for a programming error to cause most any problem! Remember, I used to teach this stuff.

But I just didn't think your tunes would be responsible).

As I said, I never tell anyone to do anything I wouldn't do. And, I think I'm fairly "conservative".

- Jack

***Power Hungry*** · #6 Mon, December 29th, 2008, 11:36 PM

The biggest issue we deal with that causes Failsafe Mode is either an overly lean or overly rich condition. This is the CAI problem with canned tunes that everyone talks about. Outside of that, there isn't much short of an actual failure.

Take care.

jerodr · #7 Tue, December 30th, 2008, 12:23 AM

This morning I did do a recalibration of my level 2 custom settings before I washed my truck. When I started the truck the engine wasn't cold cold but it wasn't warm either(I had driven it shortly a couple hours before). And the funny thing is I did do a quick shift from reverse to drive followed by quick throttle and it happened at that instant. However my truck is an 04 not an 05 like in the tsb. So I looked up the tsb for an 04 it is says that it is possible to have to replace the throttle position sensor. I think I did experience that "rare occasion" but I am wondering now if the tps is causing my throttle delay also that I was concerned about. Thanks Bill and Jack for all your help.

Jerod