# P0606- '01 Jetta Throwing Codes like Mardi Gras



## rokcandy3 (Sep 24, 2008)

For about a month now, I have been routinely clearing codes in my 2001 Jetta. Every time, I get P0606 (PCM Processor Fault). Sometimes, I get a P0420, which is odd because I've replaced the O2 sensor 4 times since I bought the car used in 2003. When I clear the codes, it takes about a week for them to come back, but sometimes it throws the P0420, and it ALWAYS throws P0606.








I'm a student.... I'm broker than broke. I understand that dealerships charge upwards of $100 just to check the PCM, which is more than I can afford. I've also read that there are a lot of times when its not actually the PCM, and dealers will just throw parts at it until its fixed. I really need some help determining what else it could possibly be... Any suggestions anyone?


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## Jay-Bee (Sep 22, 2007)

*FV-QR*

P06XX codes are not good, there is a fault with the software on the ECU.
I have P0605, but it's due to a flash/chip from Unitronic.
Best bet would be to find an ECU in the classifieds/Ebay/junkyards that matches your exact P/N.


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## rokcandy3 (Sep 24, 2008)

*Re: FV-QR (Jay-Bee)*

Thanks Jay-Bee. Any chance it's not actually the PCM? I am not a car guru by any means, but especially not being a car guru, I want to know as much as I can before (I can afford) to bring it in. Is it odd that it goes off for awhile? Any chance the P0420 has anything to do with the ultimate problem?


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## Jay-Bee (Sep 22, 2007)

*FV-QR*

Unfortunately it's directly related to the ECM/ECU, this is from Ross-Tech Wiki:
P0606 - Internal Control Module: Processor Fault
Possible Causes
* Control Module faulty 
Possible Solutions
* Replace Control Module 
I'm gonna guess that your other codes are more than likely coming up due to this, I work with and have been around computers my whole life, they do crazy things when they are close to dying.


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## rokcandy3 (Sep 24, 2008)

*Re: FV-QR (Jay-Bee)*

Indeed they do... unfortunately at this point the cost of the refurbed chip and installation from the dealer is far too expensive to justify considering the value of the car. 
What do I need to worry about in terms of driving the car? Is it suicide to try to use at this point or are there just certain issues it will cause if it goes? Like I said, the check engine light is not on constantly right now, and it stays off for awhile when I clear the code, but it still comes back. I definitely don't want to drive it if its a safety hazard.
Thanks so much for your help, too! It makes me feel much less helpless (even if I am)


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## Jay-Bee (Sep 22, 2007)

*FV-QR*

If it makes you feel better I have been driving my Golf with P0605 since June last summer with no issues, but my situation is a little different, my code was caused by the Unitronic chip/flash.
Hunt around for an ECU, they can be found dirt cheap if you wait for it, I found one for my car for ~50$ on ebay, but it has to be the exact same P/N.
I don't see it causing anything catastrophic, at most the ECU will decide suicide is it's only route and your car will just die, this can be bad on the highway as when an engine is off braking power and power steering is greatly reduced.


_Modified by Jay-Bee at 3:55 PM 4-23-2009_


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## rokcandy3 (Sep 24, 2008)

*Re: FV-QR (Jay-Bee)*

True, but from what I've heard I'd be really lucky to get one that actually works. They're all pretty much refurbed and my car has enough problems with its original parts. At this point, I'm just wondering how injured I'll be if it just craps out altogether while I'm driving...
I'll keep my eye out for the parts though. So far I found a couple for between $100-$300 which is far better than the $630 the dealer quoted me, but like I said, not so sure if I trust it.


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## Eric D (Feb 16, 1999)

*Re: P0606- '01 Jetta Throwing Codes like Mardi Gras (rokcandy3)*

Lauren, P0606 might not be a bad PCM, check out the pdf from VW.
http://netfev.org/rialta/vw/vw...2.pdf
States that the issue might be low voltage, check alternator, battery and battery fuse box wiring and fuses. 
The strip fuses can look good be actually be bad, they might have a hair line crack. You can test for this by carefully pushing on the strip fuse with a pencil or similar object.
The idea it to see if the fuse separates with little force, if it does you'll need to replace the strip fuse. Check the amperage rating on the strip fuse and replace with the same one. Online the strip fuse is about $0.30, expect to pay more at the dealer parts dept.
Here is a link with the fuse arrangement on the battery (bottom of list).
http://forums.vwvortex.com/zerothread?id=951306
On a MkIV the battery fuse box is a common replacement item. Either the plastic melts due to high current draw or the red wire is frayed from battery acid corrosion.
You can have the battery load tested on the vehicle, and also have the alternator tested on the vehicle with an ARBST machine or similar.
This service is sometimes free at some auto parts stores, many have stopped doing this free service. Best to ask first.
If the battery or alternator are bad and replaced, please have the throttle body adaption performed.
Best of luck!


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## rokcandy3 (Sep 24, 2008)

*Re: P0606- '01 Jetta Throwing Codes like Mardi Gras (Eric D)*

Thanks, Eric. I have been wondering about the battery as of late, the car is having some issues starting (tries to turn over but takes about 3 seconds). I believe it is the original battery in the car. Could the old battery be the reason its throwing the P0606? As for the wiring and what not, I am probably not the person to do the work, but your information will help me SO much when I can eventually take it somewhere for servicing. More than anything I've heard that dealers just throw parts at it. 
Does it make sense to form a relationship with a local mechanic as opposed to a dealer? I feel like on an issue like this, it would make sense to almost try to work alongside a mechanic, and as much as I love my VDub, I HATE HATE HATE HATEEEEEEEEE dealerships. I've been ripped off so bad another auto shop had to sue, and I've never had them actually fix a problem in one shot. Usually its about 5 or 6 tries and they charge me EVERY SINGLE TIME.







The last time I actually got the car back with a dead mouse in the dashboard. How that happened, I still don't know, and they charged me the hourly rate to dismantle my dash and reassemble it after removing the carcass. 
I've had so many problems with this car, and I seriously wonder if its worth fixing at this point. With over 100,000 miles, I know it won't be long til something else goes. I ask this with the heaviest of hearts, as my Blue Bomber has been my lifeline for about 6 years now... Does it make more sense for me to just sell her?


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## Eric D (Feb 16, 1999)

*Re: P0606- '01 Jetta Throwing Codes like Mardi Gras (rokcandy3)*

Sadly, some mechanics do take advantage of young drivers. I've been a victim of that 20 some years ago, and that is why I became a mechanic specializing in water cooled VWs.
When ever possible ask for your old parts back, if they have a core (re-buildable item: Alternator, battery for lead recycling, etc), then you can't have the part back unless you pay the core fee.
Yes a stock battery is most likely the issue, it was a common replacement for us as well as the battery fuse box.
Alternators seem to be a more common replacement on the MKIV cars than the earlier MKIII. Bosch redesigned the alternator and they seem to last as long as the original factory warranty. MKIII alternators well into the 150K mile mark, I rebuild these as a hobby.
A new battery should meet the minimum CCA as the original, you can get a battery with higher CCA as long as it fits in the existing spot (assuming you have the original plastic cover. These covers seem to break or are missing.
Mice can enter a vehicle with a hole the size of a quarter. He may have climbed in through the rain tray drain hole. Then it's just a matter of gnawing on some rubber grommets and he's inside.
Those buggers gnaw on just about everything. I've seen some damage like this before over the years.
I won't scare you with my known MKIV issues, the list is quite long and its $$$$.
This really applies to any modern VW that has plastic parts on the engine, doors, seats, dash etc. Best to read up in the MKIV FAQs, purchase a Bentley manual, and some tools for the easy stuff.
If you have a friend who likes to wrench, have him/her help you learn to DIY. Many of the common repairs are easy, but some require special tools that would cost more than having a mechanic do it. If you can get affordable special tools and a willingness to DIY, you'll save big bucks.
That is how I got my start, out of need and lack of funds.
I'm on the west coast, so I can't really offer you advice on which shop to use.


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## Massecar (Jan 28, 2008)

^^ that's how I got started too.
about the p0606....I got this code when my coil pack had a bad ground and was causing my car to misfire. I got misfire on all cylinders and the p0606. if you car is misfiring, might want to look into this. if so, let me know and i'll tell you how to fix the ground.


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## rokcandy3 (Sep 24, 2008)

*Re: P0606- '01 Jetta Throwing Codes like Mardi Gras (Eric D)*

Aw man, I was hoping you were around here. Way to blow it! Just kidding... your help is greatly appreciated. I like the sound of most of what you said, way cheaper that a $600+ part from VW. I'm in Orlando, FL for school right now, and originally from Connecticut, so as for friends? Most of them are 24 hours away, and my car barely made it down here. And, most of them told me to sell it a long time ago. 
A lot of the acronyms you mentioned I don't really know, but I get the gist of it. As far as replacements, are you pretty much recommending to start with the battery and work down your list? I don't have the cover for the battery anymore, I got my oil changed one day and then it was gone. What effect doe that have on my battery choice? Should I just stick with the same kind that is in there already? And is my car the MKIV or the MKIII?
I'm totally a DIY person, most of the time I try to work on my car though I can't even get the bolts and things I need loose. Thanks to the dealership, it took 3 grown men to get the filter off when I needed an oil change, and it was a little discouraging. Had I started with an "easier" car I'd probably be pretty into it by now. 
Mice suck, and that's really all that came down to. I was just upset they made me pay for the repair when the car had been on their lot in 90 degree heat for 6 days...
Anyway, thanks again! I'd love any more info you can throw at me (while things are getting thrown around-- ha. ha.)







<-- most awesome choice of things on the below list, so CHEERS!


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## rokcandy3 (Sep 24, 2008)

*Re: (Massecar)*

Massecar- I haven't had any cylinder problems/codes. Something crazy did happen with the cylinders somewhere around 2003 and SUPPOSEDLY (I dont understand, nor have I met anyone that does) they all kind of blew individually. The car was still under warranty then, so I didn't ask questions. They apparently replaced the cylinders or the whole engine-- I suppose that would be a good difference to know, but unfortunately I do not. Could that be rearing its ugly head now?


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## Eric D (Feb 16, 1999)

*Re: P0606- '01 Jetta Throwing Codes like Mardi Gras (rokcandy3)*

ARBST is the name of the battery tester and alternator tester. Basically an industry standard name and tool.
This is what it looks like.








Start with the battery load test, pretty sure the battery is going.
On factory VW batteries we would peel off the tape covering the cells (holes where you add water).
These batteries are branded maintenance free, but actually have removable cells.
Thanks to USA laws that protects every manufacture from suits, we have many "non serviceable parts" in our cars. In other countries, these same parts will have replacements that are not sold here. The VW ETKA parts catalog will have the picture of the part, but no part number. I use my global Etka to look up these euro parts.
So if you can't get a new battery just yet do to funds. Remove the tape off the battery cells (please protect your eyes and skin from battery acid) and add some water to the low cells.
Low cells are the ones where the water level is below the lead plates. 
I forgot to mention that the cell caps require a large flat blade screw driver to remove them. This can be a large coin or suitable scrap piece of metal with the proper dimensions.
I made my tool out of scrap metal and shaped it on a bench grinder years ago.
Topping off the battery will buy you some time.
I've got to go, will be back on-line later tonight.
I'll IM with further info.


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## Jay-Bee (Sep 22, 2007)

*FV-QR*

Great info Eric!!!


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## rokcandy3 (Sep 24, 2008)

*Re: P0606- '01 Jetta Throwing Codes like Mardi Gras (Eric D)*

Eric, YOU ARE AWESOME! If that quick fix will take care of it for a little while, it will be awesome. I'm so glad you were able to teach me about it, I felt like a dummy but now I at least feel like I have a leg to stand on and a place to start.
Since I have been having issues starting the car lately I think it makes sense that the battery is most likely the root of the cause, maybe not the whole cause though. I suppose its possible that the other issues I've had with the car (fuses that constantly blow-- or blow once and won't work even with a new one , a blown convenience system-- it pulsed for awhile before it went completely out... among other things) have also stemmed from this issue. I know VDubs sometimes have wiring issues, and assumed that was the root of the problem. I think for most of those problems its a little too late for the battery to fix the specific issues, but the voltage irregularity probably fried them. Aside from a new convenience system and either a new fuse box or something along the fuse system, I guess that's hopeless. I wish someone with your knowledge could have come around and helped me then, but I was at such a loss I couldn't even see a connection between the problems-- Hindsight is 20/20








What kind of place would you direct me to (I know you're across the country) that might have these testers for cheap? Like a Pep Boys or AutoZone type place? Or would I have to find a more specialized location such as a dealership? 
Thanks again for all your help!!!!!


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