Hi hope you can help, have an s40xs 1600vvt y2000(mid2000). My main issue is that even though i have changed the crankshaft sensor for a new oem one the car slows going up hills. My first error codes were P0335 AND P0340, both referring to the crankshaft sensor. When cold car can be hard to start with slightly uneven idling yet when automatic choke comes off the idle is fine, when warm or normal temp the car runs fine except when going up steep hills or long hills. I should add that i have changed in order, the fuel filter(oem) and air filter one year ago approx, then the vvt solenoid, then the upstream oxy sensor, only then did the engine sound like a petrol car,but still she lacked power. Bought a cheap and simple code sensor which gave me the above codes,put in the new crankshaft sensor, now more power but still an aversion to hills, cleaned the camshaft,throttle,fuel pressure sensor,checked air filter and all the fuses. With all codes cleared i end up with P0335 which stands for crankshaft position sensor circuit malfunction?. Now i am at a loss, is it the new crank shaft sensor, or fuse, or wiring to the control module?. Have put in new volvo coils and plugs, engine revs up the band without hesitation whilst resting yet when on the road feels nervy untill properly heated up, there is no leaks from the injectors, the old plugs had black dry sooty deposits on the base yet white deposits on the nose. At first it seems like a blocked back exhaust box yet there is plenty of grey/white steam exiting the exhaust, and she has passed the emissions test. I have read a lot of posts over these months which have helped but none identify the exact cause, well here's hoping.

 

Hi Johnathan, welcome to the forum.

Start out by putting octane booster in the tank. Then pump 91+ octane. There is a good chance that you are knocking. Also, check the manual and see if you are suppose to be pumping 91+ octane.

 

Thanks for that, the one thing i haven't tried is cleaning the knock sensor. M ay i add that i am not a mechanic just doing what i can. Can this sensor be cleaned successfully or does it have to be replaced? The recommended RON is 95 with 91 octane as a minimum,will check tomorrow,the recommended torque for the knock sensor is 22nm/16lbf per ft. I have tried boosters in the past without much noticeable difference. Is it hard to remove the sensor without removing major parts, i do not want to do a major overhaul?. If the sensor is done, why no code? I normally use 95octane. This is a European car with less than 100,000 miles on the clock.

 

I was not saying that the sensors were bad, just that you're knocking or timing is being retarded to avoid knocking.

Do you have a lot of weight in the car.

 

Thanks rspi, the car is not overloaded with weight or any thing else, usually one or two people at most, that's why i am at a loss. I have now also changed the camshaft sensor, now the code is P0340- circuit malfunction?. I believe if there is a problem with the crankshaft or the camshaft sensors the computer will definitely retard the timing, in that i agree. What i need is could there be a problem with the wiring to the control module(computer), or a malfunctioning circuit in the computer itself?. Is the control module for these sensors in front of the gearstick(shift)?. Thanks again for any help, if i cant solve this i am going to have to book the car in with the local VOLVO dealer for a complete diagnostic.