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Udp Check Engine

1K views 18 replies 9 participants last post by  svtfocusmansvt 
#1 ·
I recently added the focus cetral udp to my 2003 svtf and it worked great. but last week i got a check engine light, and rough idle at cold start. so i took it in to the dealer. they said that the check engine light was alternator undercharging so they replaced the pcm, before i could tell them about the udp. and the rough idle on cold start they are putting everypart under the sun on my car. so far they have replaced the tb, intake mainfold, reflashed the pcm, and now they are ordering a new set of injector which will be here on monday.

i was just wondering if anyone else has gotten a undercharge code from adding an udp or if colds starts are rougher when you add that. btw it runs perfect once it warms up
 
#2 ·
I have had mine on for a few days now and no problems at all to report so far. I still can't get over how much better the car feels when accelerating, definately a noticeable difference!
 
#5 ·
Ive had an UDP for about 7 months now (FRPP) and no problem what-so-ever. Other than undercharging, the rough idle, etc. was how mine was too...up until the SCT Tune!

The only CEL I get from time to time is for a misfire on #1 and the only thing left is an injector. Since I'm going FI soon and doing a minimum of 42#, I'm not overly concerned.

Wasnt there a battery cable recall on the normal Foci?? Wonder if there's any relation...

Then again, the UDP's purpose IS to slow down the accessories (ie; alternator) so a slower spin means less current, which means less charge..[shrug]
 
#6 ·
You shouldn't pull a DTC from just a UDP, another thing for you guys you have a DTC reader on your car if you go to the how-to and read the electronic tachometer or whatever it says it tells you how to access it their! YES the UDP will have a less charge on the battery but it will not keep it @ too low of a voltage to cause your CEL to turn on. If the dealership is replacing all of that DO NOT TELL THEM YOU PUT THAT UDP ON because they could charge you for all of the work they have done if they find out it was from that, but the sounds of it is it is not from that!
 
#7 ·
thats what i thought was wierd about it. im a mechanic so when the cel came on i did the digital tach trick and it said no dtc's and so i took it to my shop and used a snap-on scanner to pull codes. the dumb thing couldnt comunicate with pcm to get present codes but could comunicate to see all other parts of the pcm. after that i took it to my class at the tech school i got to. we have the wds scanner i.e. the new ford scanner and it couldnt comunicate either. the other thing is when i did the digital tach i checked the batt voltage and it was at 13.8 all the time. thats definatly not undercharging.
sorry for the long post im just trying to inform others
 
#8 ·
I ran into these problems last weekend. The car idled like crap and would even stall when the the headlights were turned on. After a few minutes of looking, I found a loose ground. Might want to take a look around your engine compartment for anything odd.
 
#13 ·
thats good i was just worried that you just get that code when you install an udp, well they better fix this time its getting to warm to really get a good cold start to check to see if the problem is fixed
 
#18 ·
its wierd i got another code for undercharging but it doesnt set a cel, and it only shows up when i use the wds to find it, i dont really care as long as the cel doesnt come on and i know its charging fine
 
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