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Reduced Power: mk4 Golf TDI

2098 Views 5 Replies 4 Participants Last post by  pearlgolf
I have a 2004 Golf TDI (automatic) that recently started having an issue with "low/reduced" power. The car turns over and starts fine but power is low/reduced until ~2600rpm is reached, then it performs ok at all speeds/rpms (e.g driving in stop and go traffic). Performance remains ok as long as I don't turn the car off. There are 2 error code: "Unexpected Voltage" and "EGR excessive recirculation".

With the MAF sensor unplugged, there is no low/reduced power after start-up and overall performance is ok. The "EGR excessive Recirculation" error remains however.

What do you think? Is it a bad MAF? or something else?
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It is most likely the maf, usually that is the mechanical test that you do, unplugg the maf and if runs like a champ then it is the maf, but if you would like to nail down the problem, hook it up to vag.com and it will tell you if the maf is bad.
I've unplugged the MAF on a car with a good MAF just to see what would happen. Power got a lot worse. If you say that overall performance is OK with an unplugged MAF it could really be that you're used to poor performance.

Do some datalogs of the MAF to make sure before you purchase a new one. Here are some tips on testing it: http://www.myturbodiesel.com/1000q_how_to/a4/maf.htm , you will need a VCDS cable (used to be called vag com).

Thanks for the timely advice, I really appreciate it. I'll let you know what happens.
Problem Solved

The MAF sensor was indeed bad. Replacing it eliminated the "low power" starts and lead to increased power in general and once I cleared the error codes they didn't come back. It runs just like new.

Thanks again.
:thumbsup It's amazing how this simple sensor can cause these problems without some backup or error code.
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