Fuel quality inadequate seat leon 2012 mk2

Jul 28, 2025
2
0
Hi, i have a Seat leon 1.2 tsi 2012 mk2 and i noticed sluggishness and revs at 1k idle. I got a tech to plug in VCDS and a 20045 fault code appeared that said fuel quality inadequate. I filled up with shell vpower and the car was as good as new instantly. But after 2 days its happened again. 1k revs and sluggishness. Ive been told to fill up with vpower again. But I just want to know if anyone knows about this issue and how to fix as its annoying me when driving up steep hills or need for more power.
 

R3k1355

Active Member
Oct 30, 2014
1,875
279
Yorkshire
Sounds like more than a fuel quality issue, unless you've been trying to run it on 85 Octane garbage or something?

You probably need some more thorough investigation.
 
Jul 28, 2025
2
0
Sounds like more than a fuel quality issue, unless you've been trying to run it on 85 Octane garbage or something?

You probably need some more thorough investigation.
Yeah ive been using a petrol station close to work and they were unbranded. But ive used that quite a couple times and its just happened now
 

mty12345

Active Member
Jun 17, 2011
4,123
683
bristol
Yeah ive been using a petrol station close to work and they were unbranded. But ive used that quite a couple times and its just happened now
I agree that it's most likely a fuel quality issue from that station. I'd do a few fills from shell and see if it continues.

The ross-tech website (Makers of VCDS) doesn't have a page for that code. It has a couple of mentions of it in the forums, but both were the same guy and it was never updated with a solution. Might help you to read it though as he even replaced the knock sensor without a fix.

Reading through it myself the bit where the guy mentioned the torque of the sensor bolt is a good thought. If you can see the sensor(s), might be worth checking they are secure
 
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