# 2006 VW Jetta 2.0T - Just bought, throwing 4 codes, Please help



## KCSureShot (May 23, 2011)

*2006 VW Jetta 2.0T - Just bought, throwing 4 codes, Please help(FIXED)*

Hi,

I just bought this car 30 days ago. It has been running fine until about a week ago. It has thrown codes several times. The first few times I reset them with my scan gauge. Finnally over the weekend when they came back and I noticed my engine, only while in park, would idle between 800 and 1500 RPMs I decided to have Advance Auto parts run their scanner on it. The idle is very odd. It starts at 800 RPM's then slowly goes up to 1500 then drops to 800 and repeats.

Codes found

P0642 Sensor Reference Voltage A Circuit Low
P0507 Idle Air Control System RPM Higher Than Expected
P2004 Intake Manifold Runner Control Bank 1 Stuck Open
P0171 Fuel Injection System Too Lean Bank 1

Odd thing is I noticed that the car has no air filter on it. I have been driving it for 30 days without one, I have no idea how long it has been driven before that without one. I'm going to get one today.

I don't have a warranty now and I'm really hoping this isn't some 1000.00 problem. I am mechanically inclined, have changed out motors, clutches, transmission etc on older jettas and golfs I have owned. Even changed a waterpump on a 1989 ford taurus SHO(most ford mechanics are afraid of that job). So I'm okay doing work myself if possible.

Any help would be great.

Thanks


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## KCSureShot (May 23, 2011)

*found air filter*

Just realized the air filter is on the back side of the motor near the firewall. WOW..damn germans, got to make it as hard as possible huh.


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## gmikel (Nov 10, 2010)

*ross-tec*



KCSureShot said:


> Hi,
> 
> I just bought this car 30 days ago. It has been running fine until about a week ago. It has thrown codes several times. The first few times I reset them with my scan gauge. Finnally over the weekend when they came back and I noticed my engine, only while in park, would idle between 800 and 1500 RPMs I decided to have Advance Auto parts run their scanner on it. The idle is very odd. It starts at 800 RPM's then slowly goes up to 1500 then drops to 800 and repeats.
> 
> ...


if you go to ross-tec, go to their wiki and look up codes. pretty good start for trouble shooting


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## KCSureShot (May 23, 2011)

*Yeah*

I'm looking at that site and I see basically some similar explanations as "Google" has already yielded. The issue is there are so many things that can cause whats happening. I'm going to pull the cover off tonight and inspect the PCV valve and change the air filter while I'm in there. I'll also be looking at hoses for signs of vacum leaks. I will reseat the connector to the MAF and maybe clean it a little.

If anyone else has any ideas on this it would be greatly appreciated. I decided not to pay 3000.00 for an extended warranty when I bought this vehicle. I figured with only 49,000 miles I should be safe for a while. Now I'm kicking myself.


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## releger (Dec 5, 2004)

These two are both related to the intake manifold flap actuator.
P0642 Sensor Reference Voltage A Circuit Low
P2004 Intake Manifold Runner Control Bank 1 Stuck Open
There is a TSB about this problem that came out a couple of years ago. Part of the TSB is a software update for the ECU. If the problem persists after the ECU is updated, the flap actuator motor needs to be replaced. I was getting codes related to the intake flap every few weeks. I had the ECU update done on my '06 A3 at the dealer and it took care of the problem. No flap codes since. It cost an hour of labor to reflash the ECU. Hopefully, that's all you'll need.

These two are caused by an intake air leak.
P0507 Idle Air Control System RPM Higher Than Expected
P0171 Fuel Injection System Too Lean Bank 1
You're already checking out the PCV valve and hoses. That's good. Also check the hoses to the vacuum pump and to the brake booster. I had a cracked fitting in the vacuum hose to the brake booster that was causing high idle speed and lean at idle codes.


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## KCSureShot (May 23, 2011)

*hmmmm*

I called the dealer yesterday and they checked my VIN in the computer and said all recalls has been done on this car. So I wonder if they flashed it already. If so does that mean I can go back and they will still fix the flap?


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## KCSureShot (May 23, 2011)

*oh another thing*

I tried to remove the oil cap while the car is running yesterday when i got home. I was able to remove it but it took some strength and I heard a loud resistant sucking sound as I was pulling it free. I read on these forums that that is a sure indicator that the PCV valve is bad. Is that right?


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## releger (Dec 5, 2004)

KCSureShot said:


> I called the dealer yesterday and they checked my VIN in the computer and said all recalls has been done on this car. So I wonder if they flashed it already. If so does that mean I can go back and they will still fix the flap?


I don't think the intake flap TSB is a recall, at least it's not for Audi. The best way for you to know whether your ECU is up to date is to find someone local with VCDS (VAG-COM) and have him scan your car. When you scan the engine controller, there will be some info about the control module. The info below is from my car before the update. The TSB states that the software version for my car should be 0080, and any lower revision requires the update. Notice the 0070 on the third line. That's the software version. Since the update, this reads 0080 on my car.

Address 01: Engine Labels: 06F-907-115-AXX.lbl
Control Module Part Number: 8P0 907 115 B HW: 8P0 907 115 B
Component and/or Version: 2.0l R4/4V TFSI 0070
Software Coding: 0103010A18070160
Work Shop Code: WSC 01307 444 53716

VW is different from Audi for the same engine, though. Below is the same information for a VW that I got from the golfmkv forums. Notice the software version on the third line. It's 0030. The VW TSB says the version should be 0040. If you're less than 0040, get the update and hope that fixes it. Otherwise, you'll need to replace the intake flap motor to stop the code from popping up.

Address 01: Engine Labels: 06F-907-115-AXX.LBL
Part No SW: 1K0 907 115 B HW: 1K0 907 115 B
Component: 2.0l R4/4V TFSI 0030
Coding: 0403010A18070160
Shop #: WSC 03087


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## releger (Dec 5, 2004)

KCSureShot said:


> I tried to remove the oil cap while the car is running yesterday when i got home. I was able to remove it but it took some strength and I heard a loud resistant sucking sound as I was pulling it free. I read on these forums that that is a sure indicator that the PCV valve is bad. Is that right?


The PCV valve keeps the crankcase under a slight vaccum. It's a problem when the valve no longer regulates the vaccum properly. What you describe doesn't sound necessarily wrong. There was a TSB that called for the replacement of the PCV and the hose that connects the PCV to the intake manifold if certain codes were seen. You could update those parts to the latest if yours have not been updated yet. Do a bit of troubleshooting first. Disconnect the PCV hose from the intake manifold and block off the port on the manifold. If it still idles badly, the PCV is not a problem and you need to look elsewhere. Near where the PCV hose connects to the intake manifold, there is another vacuum connection that goes through a one-way valve and splits three ways. A leak in any of these hoses will cause idle problems. Follow them and make sure there are no cracks or splits and that the ends are all firmly connected.


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## gmikel (Nov 10, 2010)

*pcv*



KCSureShot said:


> I tried to remove the oil cap while the car is running yesterday when i got home. I was able to remove it but it took some strength and I heard a loud resistant sucking sound as I was pulling it free. I read on these forums that that is a sure indicator that the PCV valve is bad. Is that right?


if you have high vacuum when you removed the oil filler cap, you prabably do not have a pcv problem. a lack of vacuum indicates a leaky diaphram or plumbing. from personal experience you should have 21 or more inches of vacuum at idle. you can get a fairly inexpensive vacuum guage and remove the iac (front dead center on intake, does not require removing a/f) and plug it in. they usually come with a cone shaped impliment to put in port. when my pcv went i had 17 in of vac.


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## KCSureShot (May 23, 2011)

*update*

So I took the engine cover off and I started looking for vacum leaks. The only thing that I found which seemed odd is hose that connects to something on the right end of the head. It's a somewhat circular medal cap like thing about 5 inches or so in diameter. It has a hose on its side that I was able to pull off very easily. Not much was holding that one. When I pulled it off the engine almost died and ran badly. I put it back on and it runs good. I swear I can hear a feint vacum leak coming from that area of the motor. The entire time I had that engine cover off and was testing this I had the Mass air flow sensor disconnected and my engine was running fine. I even drove the car up and down my street no issues. Once I reatached the mass air flow sensor the engine starting doing the 800rpms up to 1500rpms then drop to 800 rpms and so one. I unplug the mass air flow sensor it stops doing that. I plug it back in it starts doing it again. Is it possible the mass air flow sensor is bad and thats causing the motor to fluctuate on idle which is throwing the other codes?


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## gmikel (Nov 10, 2010)

*sounds like the mass air sensor*



KCSureShot said:


> So I took the engine cover off and I started looking for vacum leaks. The only thing that I found which seemed odd is hose that connects to something on the right end of the head. It's a somewhat circular medal cap like thing about 5 inches or so in diameter. It has a hose on its side that I was able to pull off very easily. Not much was holding that one. When I pulled it off the engine almost died and ran badly. I put it back on and it runs good. I swear I can hear a feint vacum leak coming from that area of the motor. The entire time I had that engine cover off and was testing this I had the Mass air flow sensor disconnected and my engine was running fine. I even drove the car up and down my street no issues. Once I reatached the mass air flow sensor the engine starting doing the 800rpms up to 1500rpms then drop to 800 rpms and so one. I unplug the mass air flow sensor it stops doing that. I plug it back in it starts doing it again. Is it possible the mass air flow sensor is bad and thats causing the motor to fluctuate on idle which is throwing the other codes?


if it runs good without the mass air disconnected and lousy with it connected, sure sounds like its bad.


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## spiritrider1 (Jun 3, 2011)

*MAF may not be bad*

I recently installed a Carbonio intake from APR and the instructions tell you to idle the car without accellerating for 10 minutes to allow the computer to "learn" the new air flow rate. 
I also ran my A3 up & down my street w/o air box attached and found the car drove just fine also. 
Try the idling thing and see if that helps.


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## releger (Dec 5, 2004)

KCSureShot said:


> So I took the engine cover off and I started looking for vacum leaks. The only thing that I found which seemed odd is hose that connects to something on the right end of the head. It's a somewhat circular medal cap like thing about 5 inches or so in diameter. It has a hose on its side that I was able to pull off very easily. Not much was holding that one. When I pulled it off the engine almost died and ran badly. I put it back on and it runs good. I swear I can hear a feint vacum leak coming from that area of the motor. The entire time I had that engine cover off and was testing this I had the Mass air flow sensor disconnected and my engine was running fine. I even drove the car up and down my street no issues. Once I reatached the mass air flow sensor the engine starting doing the 800rpms up to 1500rpms then drop to 800 rpms and so one. I unplug the mass air flow sensor it stops doing that. I plug it back in it starts doing it again. Is it possible the mass air flow sensor is bad and thats causing the motor to fluctuate on idle which is throwing the other codes?


 That thing on the end of the head is the vacuum pump. A leak there could cause your idle problems. Is the hose cracked? Is the gasket in bad condition? Pull the hose off the vacuum pump and plug it. Run the engine with the MAF connected with that hose disconnected and plugged. Does the idle improve? Also follow the other vacuum hose branch that goes under the vacuum pump. It connects to a hard fitting just under the vacuum pump and then another piece of hose goes from the back side and connects to the brake booster.


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## KCSureShot (May 23, 2011)

Okay, I'll try that vacum test. I did take my MAF off the car and cleaned it but it still acted up once I re-installed it. The thing I'm not 100% sure of is if it's bad or not. I un plug it and my idle problem goes away, but is that because the MAF is bad or is that because when it's plugged in the problem shows itself, but not as a result of the MAF...make sense? 

I have also had twice now in the past week my car flash the "Low oil pressure" message thing. I checked my oil and it's full. I'm really starting to get nervous about the purchase of this car. Considering resetting the codes and driving it to the nearest dealer of any make and model and trading the thing in.


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## releger (Dec 5, 2004)

KCSureShot said:


> Okay, I'll try that vacum test. I did take my MAF off the car and cleaned it but it still acted up once I re-installed it. The thing I'm not 100% sure of is if it's bad or not. I un plug it and my idle problem goes away, but is that because the MAF is bad or is that because when it's plugged in the problem shows itself, but not as a result of the MAF...make sense?
> 
> I have also had twice now in the past week my car flash the "Low oil pressure" message thing. I checked my oil and it's full. I'm really starting to get nervous about the purchase of this car. Considering resetting the codes and driving it to the nearest dealer of any make and model and trading the thing in.


 I'd sort out the intake air leak problem first before suspecting the MAF. Does the car run well except for idle? Does it have good power? If you don't have other symptoms except the bad idle, there may be nothing wrong with the MAF. When you unplug the MAF, it puts the ECU in limp mode because it has to operate without the MAF reading. Take a look at this PDF from Ross-tech for info on diagnosing MAF problems. 
www.ross-tech.net/vag-com/advertising/DiagnosingA_MAF_TechTip.pdf 

I hope your "low oil pressure" is a sensor problem rather than actual low oil pressure. You might be better off bringing the car to a specialist and getting these problems looked at.


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## KCSureShot (May 23, 2011)

releger said:


> I'd sort out the intake air leak problem first before suspecting the MAF. Does the car run well except for idle? Does it have good power? If you don't have other symptoms except the bad idle, there may be nothing wrong with the MAF. When you unplug the MAF, it puts the ECU in limp mode because it has to operate without the MAF reading. Take a look at this PDF from Ross-tech for info on diagnosing MAF problems.
> www.ross-tech.net/vag-com/advertising/DiagnosingA_MAF_TechTip.pdf
> 
> I hope your "low oil pressure" is a sensor problem rather than actual low oil pressure. You might be better off bringing the car to a specialist and getting these problems looked at.


 The car does seem to run differently with the MAF installed. It seems to have sporadic loss of boost or power. It doesn't seem to feel as powerful as it did when I first bought the car a month or so ago. When I run the car with no MAF it seems to run as it did when I bought it. I'm sure the low oil pressure is a sensor thing as it only has done it a couple of times but the car runs fine and shows it has oil. I'm worried that the oil has not always been full synthetic and I'm certain the current oil is not sythetic. which sensor whould you think it is? 

Also I'm trying to avoid taking it to a dealer or specialist as I don't want to pay hundreds of dollars for them to tell me it needs several hundreds of dollars of repairs. I will do this if all else fails, but if I can pinpoint the issue myself I can fix it myself.


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## KCSureShot (May 23, 2011)

*Problem fixed*

I purchased and installed the PCV fix by BSH and the car runs great now. So far no codes and no more idle issues. In fact the car runs so much better it's crazy. I highly recommend anyone with this motor to replace the PCV with this kit from BSH called BSH Bulletproof PCV Revamp. I ordered mine from DBC llc in Texas and had it shipped.


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