Re: Got a MIL code, can someone tell me what it me
I have just been through the P1550 experience on my 1998 Jetta TDI, and the resolution to my problem is not quite like anything I've seen anyone suggest here before. I spent a lot of time reading through posts on the subject here at TDIClub.
I had the same problem everyone describes in this case... Car ran fine after start up, until I exceeded certain RPM or speed, depending on the gear I was in. I consistently ended up in the so-called "limp mode". I went through the process of checking and replacing all vacuum lines to the N75, replacing the N75 itself, and otherwise, plenty of head scratching.
Finally one day, I was determined that I was going to get into the intake duct near the EGR valve, expecting to find that it was severely plugged up, as you can find in several similar posts on this site. As I was removing the pressure return hose from the intercooler where it feeds air to the intake through the EGR, I discovered no soot buildup at all, and about a 2 inch crack in the rubber hose.
As an experiment, I got what I thought was some sturdy duct tape to seal the crack temporarily. It didn't last for very long, but it proved that I had found the problem, as I was experiencing power and boost like I hadn't experienced in this car before. Naturally, the local dealership parts counter wanted $93.XX for a replacement, so I took the defective hose, which happens to bear a strong resemblance to a standard radiator hose, to a local auto parts store. I convinced the parts monkey to let me into the back to find a radiator hose that had a similar bend in it with the same diameter. Two new clamps, and a $9.18 radiator hose cut to the appropriate length later, and I have now driven over 600 miles with no loss of power, and after about the first 35 miles, the check engine light went out and stayed out. Did a highway trip and maintained 75+ mph with the ability to accelerate on demand, well beyond that speed if I needed to... No problem.
Bottom line, if you're in limp mode and you have a P1550 engine code, closely check the integrity of your boost hoses between the turbo, the intercooler and the intake. There are several hoses in that path. I wasted $58 on an N75 valve and $10 on some new vacuum lines for no good reason.
