# Low Pressure Fuel Sensor - P2539 - Open Circuit - Bad low pressure sensor?



## eger (Oct 29, 2007)

So I just recently did some upgrades (APR HPFP, APR DP, APR IC, new NGK plugs, new coilpacks, APR stage 2+ upgrade) and a coupe days after I got a CEL that came on a hasn't gone off. I also notice hesitation at low RPM and rough idling (both which seem like they could be low pressure sensor related).

I used this as an excuse to finally get VAG-COM and this is what I see in an engine fault scan:


```
009529 - Low Pressure Fuel Sensor (G410) 
               P2539 - 001 - Open Circuit - Intermittent
             Freeze Frame:
                    Fault Status: 00100001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 133335 km
                    Time Indication: 0

             Freeze Frame:
                    RPM: 0 /min
                    Load: 0.0 %
                    Speed: 0.0 km/h
                    Temperature: 32.0�C
                    Temperature: 31.0�C
                    Absolute Pres.: 1000.0 mbar
                    Voltage: 12.319 V

000665 - Boost Pressure Regulation 
               P0299 - 002 - Control Range Not Reached - Intermittent - MIL ON
             Freeze Frame:
                    Fault Status: 10100010
                    Fault Priority: 2
                    Fault Frequency: 3
                    Mileage: 133424 km
                    Time Indication: 0
                    Date: 2013.06.04
                    Time: 16:10:09

             Freeze Frame:
                    RPM: 4008 /min
                    Load: 92.5 %
                    Speed: 80.0 km/h
                    Temperature: 96.0�C
                    Temperature: 21.0�C
                    Absolute Pres.: 1010.0 mbar
                    Voltage: 13.843 V
```
Is it possible the low pressure fuel sensor is just bad or could it be related to plugs or coilpacks? Anything else to check now that I have VAG-COM?


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## Tutti57 (Jun 20, 2011)

I believe the fuel code has to do with your thrust sensor which might be one of the current campaigns. Call the dealer with your vin and it might be a free replacement. 

The other one could be that your stock dv is shot. 

http://wiki.ross-tech.com/wiki/index.php/16683/P0299/000665


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## eger (Oct 29, 2007)

I am already on the rev D "piston" type DV (checked it once before, super pain to get under there). Still common for the piston type to fail?

Also, from my searching, it looks like the "thrust sensor" is the same thing as the "low fuel pressure sensor"? I was looking at the diagrams listed under item 10 here: http://www.golfmkv.com/forums/showthread.php?t=24952

At least they are both something I can replace myself - now to narrow down which to try first...

I also used VAG-COM to graph my boost under load (two quick 3rd gear pull down the street). The light purple-gray line is boost and red line is RPM: https://docs.google.com/file/d/0Bxi-eDfuuzXCYnVIbHVydURYRUE/edit

Since it looks fairly smooth, would this be an indicator that the DV is working OK?


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## Tutti57 (Jun 20, 2011)

eger said:


> I am already on the rev D "piston" type DV (checked it once before, super pain to get under there). Still common for the piston type to fail?
> 
> Also, from my searching, it looks like the "thrust sensor" is the same thing as the "low fuel pressure sensor"? I was looking at the diagrams listed under item 10 here: http://www.golfmkv.com/forums/showthread.php?t=24952
> 
> ...


It's not likely to be the dv if is is the piston style. 

Try doing another log and select the boost (actual), boost (specified), and N75 duty cycle. They are all around block 114.


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## eger (Oct 29, 2007)

Here are 2 3rd gear pulls. Is it normal to have actual boost that far off specified?


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## LilLuke (Jan 20, 2013)

Did you ever figure out what the problem was? Did you change the low pressure sensor? I have the same code but its not a cel, it's just stored and my 06 gti feels like its been falling on its face after 4k rpm. I'm apr stage 2+ with supporting mods.


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## Millennium Falcon (Jan 29, 2004)

Im still dealing with this **** my self. I replace the thrust sensor (under the intake mani) the sensor on the left side of the HPFP, new fuel filter, basically brand new rs4 injectors (had em cleaned and blueprinted from rc engineering :thumbup


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## Jacoberra (Aug 4, 2020)

Last week I get tuned my audi car tyres from fortitude .com in good quality and cheap rates. They get the upgrades on low rpm on https://education.media/7-tools-that-will-help-you-write-and-proofread-that-essay and the average is increased by 2 km.


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