Hi there I hope someone can help, I have an 04 plate s60 diesel and every now and again when under load the car goes into limp mode. If we pull over and turn the car off and restart it it’s fine again for a while. Any ideas ?

thanks
mark

 

Unfortunately I have experience with this situation both personally and through a friend. I have been working on cars since I was old enough to hold a flashlight for my dad. So for about 40 years now. Do most repairs myself. Although not a mechanic, do have lots of mechanical experience with cars. So the exact same thing happened to myself and to a friend of mine. Car would all of a sudden seem to get stuck in one gear no matter how much I pushed the gas pedal down. Even though I just said I’ve been working on cars for many years, for some reason I had never heard of limp mode. So I just turned the car off, restarted it and everything was good. However, usually if your car goes into limp mode it is letting you know that something really bad and expensive is about to happen unless you take of the problem now...still might be expensive though. So your computer is receiving information from somewhere that is drastically outside it’s preprogrammed settings. From the transmission. Referred to as a fail code. So what happens is that your car senses something is wrong, let’s you know, and then turned off the solenoids in the transmission so it won’t change gears. Usually stuck in second or third gear. This is to try to prevent major damage from happening to your transmission. I highly recommend you get it checked right away. In my case I ignored it and kept turning the car off and on long enough that my transmission went out. It happened to be a CVT transmission (which I will never own again) and they are almost always never worth repairing because it’s going to cost more than replacing it. Also they don’t really make parts to fix them. In my case a remanufactured tranny with other parts and labor was $3500. More than the car was worth. So if you haven’t already, I recommend you get it looked at immediately. Otherwise “something bad” will happen and most likely you’ll be faced with a few thousand dollar repair bill. Good luck.

 

I had this problem with a '94 Mercedes E300 (gas) In this case, it was the traction control system. The car would decide (on a dry summer day) that it detected wheel spin and reduce power to regain traction. As in the above examples, turning the car off and re-starting solved the problem temporarily. The problem was eventually traced to a fault in the wiring harness. Mercedes had chosen, for some idiotic "green" initiative, to specify biodegradable insulation for this application. The fault nearly killed me on one occasion when I was merging onto an expressway with what I thought was ample room ahead of a large truck and experienced a sudden power loss. Mercedes refused to accept any responsibility for the $1700 repair. I traded the car not long thereafter and will never buy another Benz.

 

And Toyota used (up until recently) soy-based insulation on its wiring harness. This was like ringing the old dinner bell and calling for rodents from near and far. This had a similar effect and dash lights of every kind would light up. Ask me how I know !