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VW Golf check engine light

I have a 1997 VW Golf that has the check engine light on and will not pass MA emissions inspection. The codes that are coming up are P0411 and P0422. The dealer says that I need to replace the secondary air pump ($1035) and the catalytic converter ($685) to fix it. A local repair shop suggested that I try just replacing the air pump first and see if that clears the codes, but they also quoted me $1000 to do that. The car runs great, has 113,000 miles on it and I already replaced the catalytic converter 2 years and about 15,000 miles ago. I just can’t stomach putting $1000 to $2000 in it when it’s running fine just to get an inspection sticker. Any ideas for a cheaper fix?


I have to wonder if there are ANY shops / mechanics out there who are NOT throwing parts at problems shown by the check engine light?!!
The codes shown by the check engine light are DIAGNOSTIC codes which indicate problems with certain CIRCUITS, not with certain parts!
Your car needs troubleshooting for both DTCs (Diagnostic Trouble Codes). IF you search, you may find a shop / mechanic who CAN, and WILL, perform the appropriate troubleshooting; rather than throwing very expensive parts at them. Good luck.

Thanks, your comments were along the line of what I was thinking. Now to find a mechanic…

Assuming you actually do have a bad secondary air pump you could consider fishing around here for one.

I would have a hard time suspecting a 15k miles converter has gone bad again unless there is an underlying reason for it. (chronic engine miss, running too rich, coolant leak, etc. but since it runs fine these should not be a problem)

P0411 Secondary Air Injection System Incorrect Flow Detected
P0422 Main Catalyst Efficiency Below Threshold (Bank 1)

The air injection system pumps air into the exhaust pipe to improve the efficiency of the catalytic converter. With a loss of air pumping in, the catalytic converter does not clean up the exhaust as well. The problem with the air pump could be causing both DTCs.

These DTCs will not affect the driveability of the car. Basically, the car is not cleaning the exhaust from the engine as it should. This means the exhaust is dirtier than it is legally allowed to.

Did they double check any of the control valves for clogs? How about the check valve? These systems have check valves to prevent the exhaust from back-flowing into the air pump.

I finally found a source for the air pump, and they are shipped from Germany. The cheapest I found was $509. Maybe their parts sources were higher, plus labor would be about right for $1000 total.

i have had a similiar problem a couple times.

the air pump is often killed. this makes the cat get killed (due to getting over rich exhaust into it.) the underlying cause is often the mentioned “check valve” if the check valve fails, the air pump dies. when the air pump dies the cat get screwed up from the out of whack exhaust.

if all the possible problems aren’t looked into, then this problem will just keep occurring, making you broker and broker.

i would suggest that you need another mechanic look at it. just throwing parts at it WILL eventually get it fixed, but at what cost.

Thanks for all the advice! I found a mechanic who was willing to take a look at it - he cleaned up the connections to the air pump and got it working. Unfortunately I apparently cooked the cat by driving it without the air pump working, so I need to replace that, but still the repairs are costing me 700 - less than 1/2 the original estimate.

Good to hear that you found that mechanic. Kudos to him for doing something other than trying to make a quick buck…like the others…including that vaunted VW dealer. Now, if there were just a whole lot more mechanics able and willing to follow suit…

I don’t. For most repairs there are flow charts that a technician should follow. To properly diag a customers complaint. If they aren’t doing it, don’t bring it in.

You’ll have to pay the price to troubleshoot. And you have to put it into consideration that you were quoted brand new OEM German parts. I’m sure it will cost you a mighty penny and so would a O.E.M lug nut.

Best way D.I.Y, do a little research online.
Learn how it works, maybe you’ll even get to learn something new.

Don’t whine or bi+ch it aint getting you rich- LL