vag-com check for fuel filter flow


Veteran Member
Aug 16, 2004
Maui Hawaii
2004 Jetta Wagon
ok all you vag-com ers check this out using your vag -com go to engine, click 08 value block then 023 readding for fuel filter flow will show -50 and above will be filter gettiing plugged, a good filter will show -50 and below, check it out this solved a few no power concerns i have had with p/d also it doesnt matter what fuel your using. i have seen both,


Well-known member
Sep 22, 2004
heh. i was working on my new TDI PD at work here (they let me do warranty work on my own car....sweet) and i was getting crap fuel economy, and loads o smoke...

couldnt figure it out, then the help line told me to log block 23...had -10 to -25 at idle...

replaced the filter, and now the car feels like it has another 20 lbs of torque!

have to wait on the fuel economy thing tho..hope it fixed it


Nov 15, 2004
2004 silver Jetta Wagon
A couple of questions about Group 023 readings...I just did a fuel filter change on a 2004 Jetta TDI Wagon (PD) and took before and after readings. The before graph is here:

and the after fuel filter change graph is here:

1) My LBL file says these 023 readings are injector timings in microseconds. Is that a misnomer for the PD engines?

2) My "before" idle numbers were -50, -60 in that area. My
after numbers are -20, -30 in that area. When you say "will show -50 and above will be filter gettiing plugged, a good filter will show -50 and below" by above do you mean -60, -70, -80 etc. and correspondingly by below do you mean -40, -30, -20, -10? (the negative signs could get things confused by above and below). If so my graphs would indeed show improved fuel flow. But if you meant above and below in math major terms, then my data seems to show the opposite effect!

3) Do the 4 cyclinder numbers show fuel flow to each cylinder individually?

(The graphs were taken with automatic in neutral just idling, with some higher RPM revving in the middle of the run.)