COLD START LIMP MODE
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HERES THE SAME POST ON ANOTHER FORUM
http://forums.vwvortex.com/showthread.php?5954175-17705-limp-mode-on-cold-start
I've been getting the error code 17705/P1297/004759 - Pressure Drop between Turbo and Throttle Valve (check D.V.!) on the first cold start after clearing the code from the ECU. I think the code might occur the first time I hit the boost in the morning. The code isn't illuminating the CEL.
If I shut down my car and start it back up again, the car boosts normally and generally performs fairly well. I might have a slightly rough idle at times, but for the most part it's fairly good.
Mods are:
Unitronic Stage 2 POST MENTIONS FAULT WAS CAUSED BY UNITRONIC TUNE HE CHANGED TUNER?
EVOMS V-Flow
Forge 007P (relubricated, old o-rings)
42DD downpipe
Milltek catback
034MS breather hoses (with check valve)
Replaced primary O2 sensor
What I've done:
Eliminated any boost leaks
Attempted to eliminate any vacuum leaks
Cleaned throttle body
Reasonably new MAP and MAF sensor
New spark plugs which are properly gapped
Serviced diverter valve (but I reused the o-rings)
On a cold start, the idle also takes a longer time to go down to the typical 700-800 RPM. It will idle high and when it starts to drop, it takes a long time to drop, whereas it would typically drop quite fast to its normal idle. The only other anomaly I can point out is that if I'm sitting at a light and I rapidly tap my brakes, I can make the idle bounce around erratically. I don't know if this indicates an issue with the brake booster check valve which could be contributing to my slightly rough idle at times.
After searching it seems like this is a nagging error code that a lot of people just learn to live with, but I would like to eliminate it if I can.
leak diagnosis rpm needs to be raised
Is your n249 deleted? If it isn't, try running a line from the intake manifold directly to the DV. I also had a
problem where my n249 somehow became covered in fluids through no fault of my own and I had to just resistor the harness. Replacing the check valves on the brake booster could be the fix too
I have my N249. I'll try doing the line to the DV.
What about the suction jet pump? I know it is an element in the vacuum system and doesn't it have a line that goes to the brake booster? I suppose the check valves are an inexpensive attempt at a solution
its a limiter in the file. needs to be edited by a tuner. Really? A Unitronic issue?
It's the tune seen it several times with this same setup. Make them fix it
My uni file had it all the time. I never got rid of it with Uni but as soon as I switched tunes it was gone and has never returned.