Has anybody had a code p1556 Charge pressure control negative deviation? I have terrible boost problems in the lower gears.

 

#1 search

took me less than a minute to find a post linked to this

http://wiki.ross-tech.com/index.php/17964/P1556/005462

 

thanks

 

About the n75 valve, I seem to get full boost in the higher gears, wouldn't that make it unlikely to be that?

 

I used to have that code and limp mode every time I'd take it past 5k WOT through every low gear 1st-3rd in my 2000. After a restart it was fine until I did it again. Basicaly it means the ecu is seeing less boost than it requested. You could try removing and cleaning your map sensor (on top of the ic) or it could be a faulty n75. This started happening after I got chipped. I never did figure it out, but I hardly ever drive wot to red line through every gear like I used to either. Seemed to be less likely to happen when I was using the n75 race valve and never happened when i used a mbc (but the mbc gave me other issues.) Good luck.