CEL and Emmissions Workshop comes on and goes off - VW Passat 2001

Maintenance/Repairs
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1

I drive a VW Passat 2001 (1.8T). It has around 104K miles.



The check Engine light with Emissions Workshop indication comes on and stays for around 150 miles. The car drives fine (without alerts) for another 150 miles before the alerts come back. This has been going on and on and on …



I took it to a local mechanic. He checked the code (don’t remember) and replaced vew vacuum hoses. The problem came back after 1 day. He replaced the O2 sensor. That didn’t fix the problem either. He told me that there might be a minor vacuum hose leak somewhere and he doesn’t have the special tool to detect the leak. He told the car will drive fine but for little less mileage.



I get around 28 miles per gallon in mix city and freeway driving. I think the mileage might have gone down by 1-2 miles per gallon.



I have been living with the problem for over 3000 miles now.



Any idea what might be going on? I am surprised how the problem starts and goes away of its own.



Any recommendation?

2

Go to Autozone or similar car parts stores and have the CEL scanned…most often for free.
Come back here and post the exact CEL code (Pxyzk, etc)

I would definetely look into a VW specialized, INDEPENDENT shop. This mechanic seems to just throw darts in the dark, and not even posses the most basic tools. Use the links here to locate some in your area. Read up the reviews on them, visit a few shops see how they look (clean, dirty, etc) talk to the owners/mechanics, and only then choose one to give them your present and future business. Then develop a business relationship with that shop.

I hope you’re changing the oil on this car EVERY 5000 miles (and I do not mean 5973), and with a fully synthetic one at that.

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3

The mechanic checked the code for me. Its P0171.

4

The mechanic checked the code for me. Its P0171.

He didn’t find any vacuum hose leak and recommended the following - says it will also fix the problem with “rough idle” in my car:

  1. The MAF (Mass Air Flow) Sensor is dirty or faulty. He recommended to change it. The cost of parts from dealer is $190.
  2. Throttle Body cleaning
  3. Retune the car after these changes. He doesn’t have the equipment to retune the car and has to take it to a dealer who will change $110 for the work.

I asked him if MAF can be cleaned instead of replacing. He thinks its better to replace it since after cleaning and retuning if it the problem doesn’t go away then I have to pay twice for retuning.

It will cost me between $350-$400 if I follow his recommendation. He says I don’t need to hurry to get this done but should not wait for too long. What do you guys think about the recommendation and cost?