# 2004 Beetle and P2187 OBDll code



## chuck wisher (Jun 12, 2011)

i currently have a 2004 beetle convertable, BGD 2.0 liter normaly aspirated 4 cylinder with a six speed auto. This vehicle has 185,000 miles on it, the tranny finnaly gave up and the check engine light came on all at around the same time. Well the trany was just too expensive to fix at the time and the check engine light apperaed to be the upstream O2. So I put the car in storage, about a year past and I needed the car, the trany was repalced anthe check engine light was followed up on. The primary O2 was changed and the computer scan now shows the sensor operating where the original was sluggish and non-changing with respect to the voltage. all looked good and three hours later on the road the check engine light came back on, P2187 is the fault code. The following have already been repalaced recently: spark plugs and wires, coil pack, fuel pump and filter, upstream O2 sensor.i can find no obvious vacuum leaks and the MAP has never caused a problem in the past.
Any ideas what might cause a P2187 fault code in this case?
Chuck


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## arcticcode13 (Feb 28, 2012)

someone else had this issue here is the link to theres


http://forums.vwvortex.com/showthread.php?5195799-P2187


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## Anony00GT (Mar 6, 2002)

It's tough to accurately diagnose this kind of thing if all you've got is a generic OBDII scanner, VCDS is highly recommended here. Generic OBDII will probably refer to this code as simply "manufacturer controlled emission control" or something of that nature.

18619/P2187/008583 - Bank 1; System too Lean at Idle

Firstly, what was the original fault code for the O2 sensor? And was it replaced with a good OE/Bosch part, or something else? Those are the only O2 sensors to use for your application, OE or direct-fit aftermarket Bosch.

Also, check for vacuum leaks and check the MAF. With a generic OBDII datastream, you should be able to observe MAF readings (g/s), as well as fuel trims. That could be helpful enough, but you'll need VCDS to run Basic Settings and verify anything.


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## chuck wisher (Jun 12, 2011)

*2004 beetle and P2187 fault*

Thank you for your response, to answer your question the O2 is a OEM bosch sensor.
As for the rest of the car..........once again the same code came up after the wife drove the car. And this was after following a list of all possible causes, including cleaning the MAF sensor and check for any type of vacuum leak.....with no results. The laptop shows the data from the engine running right down the middle of the sales none to high and none too low. So after staring at the laptop this morning and arguing with the wife I had enough...............i packed the car up and took it to a shop. I don't know what I keep missing, but if I haven't found it yet, the chance are I won't. Time for a new set of eyes on the problem...........and more exposure to VW's. Thanks again, but I have had it.

Chuck:banghead:


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## Anony00GT (Mar 6, 2002)

Please update the thread with the fix when it's resolved. It may help others in the future.


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## chuck wisher (Jun 12, 2011)

*2004 beetle and P2187 fault*

greetings to all.
heres the update........after spending $500. i found that yes the engine computer did "see" a vacuum leak. I just was looking in the wrong place, the charcoal canister located behind the right rear tail light.....these sneekly europeans... was damaged. the plastic pipe that runs from the top of the canister to the throttle body was broken off.....Surprise!!!!!!. In thity years of Comercial Fleet work I have never seen a canister fail this way. well with the vacuum line clamped off the Lean code stop....however to my surprise I was now getting random missfire codes and a code for the the downstream O2 not heating up fast enough, add to this the need to have a new york state emissions inspection and like magic...............$500. bill. will I have the beetle back and it runs fine for the moment, but I still have the charcoal canister problem...........no I'm not planning on spending another $500 buck for a canister,especialy when any domistic car maker charges peanuts for theirs. So, question... how do I keep the engine computer from reacting to anything from the canister evp system and throwing a Check Engine Light. Any ideas?
Thanks
chuck:what:


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## Anony00GT (Mar 6, 2002)

chuck wisher said:


> So, question... how do I keep the engine computer from reacting to anything from the canister evp system and throwing a Check Engine Light. Any ideas?
> Thanks
> chuck:what:


The only answer is to fix the EVAP system. Under federal law, it has to function properly.

If you're feeling above the law, consider this: your car needs no vacuum leaks to ensure proper A/F control, or else you can add a $1000 catalytic converter to that $500 estimate next.


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## arcticcode13 (Feb 28, 2012)

altho the above post is true there is a way to bypass the sensor....go to radio shack and get a dial (kinda like one to up the volume of a radio) and run a + pos line to it...there should be the output of the dial and use a quick connect to attach it to the +pos return line of the sensors connector and look for the voltage that the sensor would be pushing back if it was working properly....then use a volt meeter to set the dial to the correct voltage....if ur not carful tho you could hurt or destroy your computer......


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## Anony00GT (Mar 6, 2002)

arcticcode13 said:


> altho the above post is true there is a way to bypass the sensor....go to radio shack and get a dial (kinda like one to up the volume of a radio) and run a + pos line to it...there should be the output of the dial and use a quick connect to attach it to the +pos return line of the sensors connector and look for the voltage that the sensor would be pushing back if it was working properly....then use a volt meeter to set the dial to the correct voltage....if ur not carful tho you could hurt or destroy your computer......


What "sensor" are you speaking of???

I certainly hope you're NOT suggesting to wire a Radio Shack potentiometer (that's what I believe you're referring to, not "dial") into anything, especially the MAF and/or O2 sensor circuit :screwy: 

To the OP, if you do this AT ALL you'll probably destroy your computer. Horrible suggestion. Do some research on how these sensors work before you post n00b repair suggestions.


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## arcticcode13 (Feb 28, 2012)

Anony00GT said:


> What "sensor" are you speaking of???
> 
> I certainly hope you're NOT suggesting to wire a Radio Shack potentiometer (that's what I believe you're referring to, not "dial") into anything, especially the MAF and/or O2 sensor circuit :screwy:
> 
> To the OP, if you do this AT ALL you'll probably destroy your computer. Horrible suggestion. Do some research on how these sensors work before you post n00b repair suggestions.






Haha sorry I couldnt think of the name potentiometer....and I have done plenty of research and have used this on many of my own cars and never had an issue...worked on a 1999 ford taurus, a 79 datsun 280zx, 78 datsun 280z, 93 geo tracker, 2002 ford focus, 94 vw jetta, 95 geo metro, 92 dodge stealth.....sorry but its not really a "noob" comment since I know how to do it and have been able to perform this sorta "half assed" repair a bunch of times and still all of the cars above run and are legal as in inspected without "lick and stick" and seem to run without a problem.....learn your facts about what your talking about before stabbing at someone elses posts.....


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## Anony00GT (Mar 6, 2002)

arcticcode13 said:


> Haha sorry I couldnt think of the name potentiometer....and I have done plenty of research and have used this on many of my own cars and never had an issue...worked on a 1999 ford taurus, a 79 datsun 280zx, 78 datsun 280z, 93 geo tracker, 2002 ford focus, 94 vw jetta, 95 geo metro, 92 dodge stealth.....sorry but its not really a "noob" comment since I know how to do it and have been able to perform this sorta "half assed" repair a bunch of times and still all of the cars above run and are legal as in inspected without "lick and stick" and seem to run without a problem.....learn your facts about what your talking about before stabbing at someone elses posts.....


I like your reference to how it worked on OBDI (and pre-OBD altogther) cars, yet you still haven't said which sensor you'd wire this thing into 

I must have absolutely no knowledge of automotive systems, what with all my years of professional experience in the industry and certifications, right?

You haven't even said which sensor on which you're suggesting to install this potentiometer. It would work to dummy up a temperature sensor signal (albeit wired differently than you described), but today's engine computers require a changing signal even from that, a static signal that you set manually would cause nothing but problems in a 2004 Beetle.

However, your method certainly WOULD NOT work for any sensor related to this modern-day fault:

18619/P2187/008583 - Bank 1; System too Lean at Idle


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## arcticcode13 (Feb 28, 2012)

I have used this on the 1999 ford taurus for the charcoal canister sensor....and as I recall...that car is an obd 2 system...and I have use it to get rid of an o2 sensor...since you can set the voltage at a point where it tricks the computer into thinking that everything is working properly...


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## Anony00GT (Mar 6, 2002)

arcticcode13 said:


> I have used this on the 1999 ford taurus for the charcoal canister sensor....and as I recall...that car is an obd 2 system...and I have use it to get rid of an o2 sensor...since you can set the voltage at a point where it tricks the computer into thinking that everything is working properly...


"charcoal canister sensor"? Never heard of that. Please, give me the part number for that one. If you can't find it for a Beetle, the part number for a '99 Taurus will do. Are you referring to a fuel tank pressure sensor maybe? Or a vent solenoid? I'm lost.

You may be able to get away with it on a '99 Ford for a downstream oxygen sensor. There is an old Mustang trick to "fool" the computer into thinking that the cat is still there when it's gone, it was a bit more complicated than your method, but I suppose in theory a potentiometer _might_ work (still not sure if a potentiometer alone would do it, as I recall, it was a combination of capacitors and resistors wired into the O2 sensor signal circuit, while the sensor itself stayed in place, forget the details). This works because, in (now antiquated) late 1990's Ford logic, the O2 sensor was simply a cat monitor. A steady/constant 500mv from the downstream sensor would be fine by that PCM's logic.

That trick would NOT work for an upstream sensor. The upstream sensor has to switch several times each second. Not going to happen with a potentiometer.

Fast forward to 2012 (or 2004, as is the case in this vehicle). Upstream O2 sensors have been replaced with wideband A/F sensors, and downstream sensors, while still regular O2's, are now expected to switch and are given some authority in mixture control. Now your theory REALLY won't work. Let me explain:

Fault code 18619 indicates a mixture imbalance, in this case at idle. The PCM is adjusting injector pulse based on MAF input, but the A/F sensor is reporting lean. Start driving, bring the RPM up a bit, and they agree again. This is because the small vacuum leak in the EVAP line is enough to throw the mixture off at idle, but not at >2000 RPM or so. There is no sensor on the charcoal canister that will solve this problem, and there is no way to "fool" the ECU on this particular vehicle, and any attempt to do so would likely cause more harm than good. The only solution is to fix the vacuum leak.


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## arcticcode13 (Feb 28, 2012)

lol sorry not charcoal canister sensor its an evap sensor that I used it on...but it is connected to the canister where it sits...as for a vacuum leak doing something as dumb as tricking the ecu would be pointless and do obviously more harm then good....I didnt realize that there was a leak from the original comments but figured he would have fixed that issue since to make a computer not believe there is a leak is almost impossible.....


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