When applying brakes RPM's will drop dramatically

kitt57 · Post by **kitt57** » 13 Dec 2015, 00:40

I live in Dubai and own a 2000 Volvo S-70 which the engines was replaced in June/2013; since that time I have had repeated problems with ETM. I have replaced the Throttle Body with a new Volvo dealership ETM and software updated. But I am still experiencing the same problem that when applying the brakes the RPM's will drop well below the idle speed to the point the car shudders. Could this be the MAF (which I disconnected - no change), or maybe vacuum hoses? I appreciate any help or suggestions.

Post by **abscate** » 13 Dec 2015, 06:01

Welcome kitt! It's probably the brake booster check valve ( cheap) or the booster itself ( not cheap). You should also inspect all the vacuum hoses for leaks and tears too.