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gomi_otaku, VW Technician
Category: VW
Satisfied Customers: 3449
Experience:  VW FastTrack '00-'01, VW Academy Chicago and Seattle '00-present, VW Certified
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BEETLE: TURBO..EPC and ASR lights..Dealers..Throttle Body..Lights come

Customer Question

2001 NEW BEETLE TURBO Check engine, EPC and ASR lights keep coming on. Been to 2 different Dealers several times and they changed the Throttle Body and adjusted things but always the same answer we don't see any thing wrong. They reset the system then the Lights come back in a few days to a few weeks. When the lights come on the car may or may not run rough or stall. I let it sit overnight and the lights go off except the check engine light. Then in a day or so it happens again. Then Back to the Dealer where it runs great except for the check engine light is on and they say all we can do is reset it. Any input would be appreciated
Submitted: 7 years ago.
Category: VW
Expert:  Cardoctor74 replied 7 years ago.
Do you know what the codes are that were stored for the lights?
Customer: replied 7 years ago.
P0102 was the only one I know of but they said it checked fine
Expert:  Cardoctor74 replied 7 years ago.
OK the code p0102 is a problem with the Mass air flow circuit.Has this been checked?The EPC light comes on with the check engine.Usually The faulty throttle body would take care of these issues.Have seen these codes come back and need an engine harness and that would need to be checked next.These are what they need to check next.

Hoped this helped.

Positive feedback and bonuses greatly appreciated.
Customer: replied 7 years ago.
Like I said all has been checked. I was hoping for somone who seen this exact problem and had an answer. I have read online other peoples same problems but never an answer except vague ones. Thank for your time anyways
Customer: replied 7 years ago.
Expert:  gomi_otaku replied 7 years ago.

When it is exhibiting the symptoms, unplug the Mass Air Flow sensor and see it it runs better- this reverts it to a "mapped" input in the ECM instead of relying on the MAF signal. The EPC, CEL, and ASR (assisted steering response) lights all come on because this deals with torque distribution (working together with the ECM, ABS, and TCM- if you have an auto trans)

If it runs better replace the MAF

Customer: replied 7 years ago.

Thanks for trying but I actually tried that on my own with no change.

Expert:  gomi_otaku replied 7 years ago.

Ok- so other things that can cause a "low input" at the MAF are that there is an unmetered air leak after the MAF somewhere- vacuum lines are most common, but also the rubber hoses in the PCV system (under the intake manifold, and the "Y" pipe at the end of the valve cover. The "vacuum amplifier" under the intake manifold also tends toget clogged up, it is a black plastic cylinder with a rubber hose from each end (one end to the underside of the intake manifold), and one more at an angle from the middle.

Worse case scenarios are that you have a wiring issue (will need to overlay the wires from the ECM to the MAF, I have had to do this a few times so far this year) or that you actually have a bad ECM (highly unlikely, more likely to be the wiring