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2001 VW -smog test fail

Hi everyone,

So I didn’t pass the smog check for the new used car that I just purchased 10 days ago. Although my old car (same model), was five years older, I never had this problem. I was told that it is a gross polluter.
These are the problem that I have to fix:

OBD Fault Codes - P1128 Manufacturer specific code
P0411 Secondary Air inj Incorrect Flow
P0172 System too Rich (Bank 1)
P0134 O2 Sensor CKT Inactive (Bank 1 Sensor 1)

Does anyone know how high the cost runs??
And how this happens??


The fourth problem listed is probably causing the second and third problems. P1128 I show as “Upstream Heated O2 Sensors Swapped”.

I suspect you bought a car with a problem that someone tried to fix but could not so they tried to “jury-rig” it.

It happened because you failed to get the car thoroughly checked out before making the purchase. Don’t feel badly, lotsof peoeple make this mistake.

The cost will depend on how difficult it is to determine the cause of the oxygen sensor problem. I don’t think this is a simple failed part, I think it’s a wiring problem.

In Massachusetts, a motor vehicle sale can be declared null and void if the vehicle fails to pass inspection within seven days of purchase, AND the estimated cost of repairs for safety / emissions is ten percent of the purchase price or greater. I don’t know what the laws are like in your state.

Other posters are correct in stating that it would have been smart to get the car checked out before you bought it, but “lemon laws” like the one I described above can offer some consumer protection. It might behoove you to investigate and see what your state’s laws are on this subject.

If nothing else, it’ll make you a little more prepared for your next vehicle purchase, which will hopefully not be for a long time.

Here in Atl, GA, they have been trying to tell people not to buy a car without a passing emissions report. The State will refuse to tag a car without a passing report. Dealer’s know this, and that a sale can be cancelled without a passing report. It’s the private sales that are causing the hassles. This State still recognizes ‘As-Is’ for private car sales. The only other recourse is a fraud complaint in court, small claims if under $3,500.

It would help to know which engine you have, particularly 4 cylinder of V-6.

The oxygen sensor problem has to be addressed first. It is not providing an output. This is the upstream or first sensor in the exhaust, the one before the cat. If you have a V-6, it will be on the side where the #1 spark plug resides. It alone could be responsible for all the other codes.

But there is one other possibility, the secondary air circuit. All these codes are related. The P0411 and P0134 are dependent on a reading taken within a certain timeframe after starting the engine. For this reading to be correct, the air pump must be working as the engine is still cold.

The air pump is pretty expensive and often is not the problem, but the tube and/or the reed valve from the pump to the exhaust manifold could be clogged up. There is a passage in the exhaust manifold as well that also could be clogged up. If these are clogged, the following happens:

The engine is running rich because it is cold, the secondary air is not getting to the exhaust stream so there is no secondary “burn” to burn off the excess fuel at the cat. The O2 sensor is not cycling as it should because it is running too rich. You then get the P0172 code.

You could unplug the secondary air pump and check for continuity through the motor with an ohmmeter. If good, remove all the pipes and the reed valve and clean them with a spray carburetor cleaner. Also spray out the passage in the exhaust manifold.

If the O2 sensor isn’t working, it also thinks the secondary air isn’t working either. It is more likely to be the problem.

If fixing the secondary air or O2 sensor does not get rid of the P0172, then you may also have a vacuum leak, but I don’t think a vacuum leak would set the other codes.