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My daughter has a 2001 New Beetle GLS with 2.0L AVH engine... Her CEL light is on... I read the codes with my hand held scan tool and I get the following 3 codes:

P0171 - System too lean (Bank 1)
P1296 - Manuf. Control Fuel Air metering
P0420 - CAT efficiency below threshold (Bank 1)

Any clues what these are and what needs to be done?

Thanks!!
 

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If you have not cleared the codes, see if there is freeze frame data, if so write this info down and post back here for comment.

See if your tool will display fuel trim valves, get this info and post back for comment.

Check the engine coolant temp, should be running at least 205F.

Clear codes and see what one(s)come back first.

Likely there is a vacuum leak causing the MAF & Lean code??

The cat efficiency one is something I would not jump on right away. Could be a lot of things from exhaust leak, O2 sensor bung weld cracks, bad converter, ECU needing to be reflashed. This code is a known problem with these VW's and many times is a software problem. Worry about the other 2 codes first, the cat efficiency is nothing but an nuisance most of the time.
 

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I already cleared the codes... My scan tool is a cheap Actron hand held... Doesn't do much except read and erase codes... I set the trip meter in the car to 0 and told my daughter to tell me as soon as the CEL comes back on...
 

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Skip the Actron.

Read this, OBD Software and Interface $22.16 - E46Fanatics

Ignore the BMW specific info. For under $30 you can come up with something that will do a decent job for you.

If you want a handheld tool that does quite a lot, suggest you consider the Launch CReader VI.
 

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Discussion Starter #5
If you have not cleared the codes, see if there is freeze frame data, if so write this info down and post back here for comment.

See if your tool will display fuel trim valves, get this info and post back for comment.

Check the engine coolant temp, should be running at least 205F.

Clear codes and see what one(s)come back first.

Likely there is a vacuum leak causing the MAF & Lean code??

The cat efficiency one is something I would not jump on right away. Could be a lot of things from exhaust leak, O2 sensor bung weld cracks, bad converter, ECU needing to be reflashed. This code is a known problem with these VW's and many times is a software problem. Worry about the other 2 codes first, the cat efficiency is nothing but an nuisance most of the time.

Codes came back after about 20 miles of driving... But my daughter is away with the car now so I don't know which one(s) came back yet!!
 

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That's why you get a code reader and keep it in the trunk and teach the driver to use it.

Also AAMCO will read codes for free and most auto parts stores will loan scan tools for use in the parking lot except for the 3rd world country of California!
 

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That's why you get a code reader and keep it in the trunk and teach the driver to use it.

Also AAMCO will read codes for free and most auto parts stores will loan scan tools for use in the parking lot except for the 3rd world country of California!
Oh I know,I know,I know... But my 21 yr old daughter is clueless about cars... Lucky she can put gas in it... LOL... So it's "dad's" responsibility... Except for the fact she is never home!!
 

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Lean condition most likely due to a vacuum leak somewhere on the intake path.

Likely a broken or rotten rubber or plastic part.

I think a common problem on these cars is the fuel pressure regulator vacuum hose?
 

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Discussion Starter #11
Lean condition most likely due to a vacuum leak somewhere on the intake path.

Likely a broken or rotten rubber or plastic part.

I think a common problem on these cars is the fuel pressure regulator vacuum hose?
Have not found any vacuum leaks or rotted hose... I replaced most of them about 1 year ago...

Do you know what the running fuel pressure should be? We have a suspicion that the fuel pump might be weak...

Thanks
 

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I do not have the fuel pressure info handy for this car, however, usually 50 PSI is pretty typical.

Can you get Freeze Frame date for the code?? This will give a good idea if the problem is at idle or while cruising.

Also keep in mind crankcase and intake air leaks can be the cause of the problem.

If the fuel filter has not been replaced in the last 30k miles, replace it. Should be around $15 and pretty easy to change, at least on my 2003 it was easy to do. Just be careful of the quick release connectors, you DO NOT want to break any of them.
 

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I do not have the fuel pressure info handy for this car, however, usually 50 PSI is pretty typical.

Can you get Freeze Frame date for the code?? This will give a good idea if the problem is at idle or while cruising.

Also keep in mind crankcase and intake air leaks can be the cause of the problem.

If the fuel filter has not been replaced in the last 30k miles, replace it. Should be around $15 and pretty easy to change, at least on my 2003 it was easy to do. Just be careful of the quick release connectors, you DO NOT want to break any of them.
Reading about 46-48psi at idle...
I cannot get freeze frame data at this time... This is mostly an "in driveway" job at this time...
Fuel filter was change about 1 year ago also... Less than 30K miles on it...
 

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http://newbeetle.org/forums/technic...d-scan-tools-software-options-cross-post.html

Freeze Frame data is a function of the scan tool being used. Check to see if your local auto parts store has a tool you can borrow.

I would still likely say a vacuum leak. My current version of the electronic Bentley is not launching at the moment so cannot confirm the fuel pressure. But you are not far off, but also many tests also list a 1 liter volume in a specific amount of time.

Different engine, but may be useful?? https://wiki.bentleypublishers.com/pages/viewpage.action?pageId=7602510
 

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http://newbeetle.org/forums/technic...d-scan-tools-software-options-cross-post.html

Freeze Frame data is a function of the scan tool being used. Check to see if your local auto parts store has a tool you can borrow.

I would still likely saw a vacuum leak. My current version of the electronic Bentley is not launching at the moment so cannot confirm the fuel pressure. But you are not far off, but also many tests also list a 1 liter volume in a specific amount of time.
Let me know if you can confirm the pressure... Thanks...

I will look into local Auto parts stores...

Another question... Can you tell me what engine type I have as the AutoZone list 4 different 2.0L engines as:

B 2.0L SFI
K 2.0L MFI
S 2.0L SFI SOHC
T 2.0L SFI SOHC

If it helps I have an AVH motor. VIN# is 3VWCK21C21M470506
 
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