# In and out of limp mode?



## johnboywalton (Apr 1, 2010)

Hey guys need a little help here on my 01 jetta 2.0 8V. After blowing a main fuse about 3 weeks ago, I noticed the other day my EPC light came on then shortly after my check engine light. I believe I went to limp mode cuz my car has a serious lack of power and takes forever to get to rpm to shift. So I go to shucks and borrow their reader and it tells me LDP(leak detection pump) has a short or intermittent ground. I clear the code and my car runs great, until the next day, check engine light EPC light car runs weak. Go back to shucks this time it says it has bay one weak oir low pressuer or something like that. Clear it, and now back and forthe the EPC light comes on and goes off, with lots of loss of power. Now it has the EPC and CE lights on permanent and about half power, I haven't been able to go read the code yet to see what crazy thing it calls out this time. Any help, could the ECU cause this? It was raining a lot but not now and still doing this. So basically I have seen on the forums where peopl have chased their damn tails oin this limp mode/EPC stuff. Any help is great or just tell me how to turn limp mode off. 

My car runs terrific when it isn't doing this crazy stuff.


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## Jay-Bee (Sep 22, 2007)

Get the actual Pxxxx codes, make sure it's not just 1 code it's reading there could be several stored in the ECU. 

EPC has to do with the MAF and throttle body, they work together along with the ABS for the "traction control" system.


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## johnboywalton (Apr 1, 2010)

p10446 sounds right the first time, but I will go and get the next one in the AM. See what it says this time, also some of the time the CE light comes on then later the EPC goes on and off, so I will post back so any help is appreciated.


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## Jay-Bee (Sep 22, 2007)

It's gonna be P followed by 4 digits, or just 5 digits straight up with no letter. 

Either way we can work with them to figure it out when you get them.


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## dkfackler (Feb 8, 2010)

johnboywalton said:


> ... the EPC goes on and off, so I will post back so any help is appreciated.


 This can be a failed brake light switch. There was a recall for this. It sounds strange, but the EPC is the throttle DBW, and the brake light switch is used to kill the cruise control, so it does make sense. Mine failed and the EPC light would come on, the car would lose power. I'd shut it down, restart, and the power would be back temporarily. The recall brake light switch fixed it. 

These cars' systems are so interconnected, cross checked and interactive that a seemingly unrelated component can sink you.


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## johnboywalton (Apr 1, 2010)

Okay the guy at the auto parts store said that he has actually seen the temp switch cause this because the car thinks the temp is something and says that all the other sensors are off, but here are the codes 
p before all. 

0103-mass aiflow sensor cicuit, high input 
0507-idle control system, rpm higher than expected 
0638-not in my book 
0121-throttle position sensor circuit, range or performance problem 
0221-not in my book 

I know one said something about bank 1, and the other had to do with the throttle again. the freeze frame said 28mph rpm2700 or so. I cleared the codes and drove around for a bit runs great then all a sudden epc comes on, lose power, then check engine again. I turned off the car and restarted ran good tilll I hit about 20 then they both came on with almost no power I limped home and gave up for the day.


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## dkfackler (Feb 8, 2010)

johnboywalton said:


> 0103-mass aiflow sensor cicuit, high input


 What's your engine code? If it's AZG or AVH, that MAF code can be a failed ECM... 

We'll hope not.


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## johnboywalton (Apr 1, 2010)

not sure what code the engine is, where would I find that? I have an update, after letting my car sit for a few days and driving my wife's car, I finally had to drive mine to work, the check engine light was still on but the car was running great, no hesitation no nothing. I had all the usual power and oomph. Drove all over and the EPC never came on, and the car ran great. So I am wondering if this has been a moisture issue with a connection somewhere? Any ideas?


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## johnboywalton (Apr 1, 2010)

Ok so i went through yesterday and disconnected and cleaned with contact cleaner almost every sensor I could get to. After about 45 min I reconnected everything, car started EPC light went off, and ran great. Took her to temp 190, and all was good. Chck engine light still on. so later take her out stop by autoparts, same 4 codes as last time pop, clear em out, and she has been running great since. usually by now(about 5 runs) she would have popped the EPC already so whatever i did lets hope it fixed er. I am thinking it might have been a bad connection on the throttle body box.


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