glow plug light flashing after installing boost gauge

[Ichbenscneil]

so i have a mk4 1.9 alh and i installed a boost gauge yesterday set it all up connected it through the rubber pipe right before the egr valve and siliconed it all so there werent any leaks and i went to test it out and my glow plug light is flashing i thinks its possibly boost leak

 

[oilhammer]

OBD works, start there.

 

[Ichbenscneil]

OBD works, start there.

ive used my obd2 scanner and it says my boost is fine not and leaking sitting around 999.6 mbar of boost when revving and no engine codes are showing and i pulled my glow plugs just to make sure they werent too bad and there was a bit of carbon build up but they all seemed fine

 

[oilhammer]

You need a better scan tool.

 

[Vince Waldon]

If the glow plug light is flashing there are most definitely codes set, but they will be VW-specific and you'll need a VW-specific scanner like VCDS to pick 'em up.

It will be one or more of the following (none of which directly relate to a boost leak):

00741 Brake pedal monitoring - implausible signal

01044 Control unit incorrectly coded

16705/P0321 Engine speed sensor - implausible signal

16706/P0322 Engine speed sensor - no signal

16955/P0571 Brake light switch (F) - implausible signal

17653/P1245 Needle lift sender (G80) - short to earth

17654/P1246 Needle lift sender (G80) - Implausible signal

17655/P1247 Needle lift sender (G80) - Open circuit/short to positive

17762/P1354 Modulating piston movement sender (G149) - electrical fault in current circuit

17969/P1561 Metering adjuster (N146) - control difference

17978/P1570 Engine control unit blocked

18020/P1612 Control unit incorrectly coded

18026/P1618 Glow plug relay (J52) - short to positive

18027/P1619 Glow plug relay (J52) - open circuit/short to earth

18040/P1632 Accelerator position sender - voltage supply

 

[Ichbenscneil]

Alright i'll look into getting a vcds or maybe finding a shop that has one. I was looking at my live data on my scanner and it showed up as everything working fine the only thing i couldnt test was my glow plug relay and modulating piston movement sender but idk this is my first volkswagen and i'm not to familiar with the TDI i've worked on it some but just basic stuff so far.

 

[oilhammer]

All cars, but ESPECIALLY German ones, are finicky about scan tools. The "generic" OBD2 stuff only lets you into a small section of the ECU, because that car's engine control system is essentially speaking two languages, and it isn't very good at one of them. You get a proper scan tool that speaks fluent Volkswagen, and you'll get MUCH further and since almost all of us here use VCDS we can much better help you if you have that.