Hi. I am having a problem where I can start my 2009 S40, back up just fine, but when I put it in gear, It starts to accelerate for a second, then stops. If I hit the brakes, then give it gas again, the same thing happens. It only does this for a couple minutes, then the red Brake Failure light and warning comes on, then it runs fine. The ABS light and No Rear Belt in Use warning keeps popping up too.

 

When you say "stops"... what do you mean? The engine dies? The transmission disengages? The brakes come on?

 

I mean it stops accelerating. The engine will start to rev up for maybe half a second, then it's like I just let off the gas pedal. It still coasts forward if i just idle, and it doesn't feel like the transmission is slipping. I'm fairly sure it's an electrical issue, but I'm not a mechanic by any means.

 

start by having a diagnostic scan for any stored codes. It almost sounds like the gas pedal is not moving the throttle. These cars are drive by wire so it could be related to the pedal position sensor or possibly the electronic throttle mechanism or a transmission speed sensor (which ties into the ABS)