I have a 2005 XC70 AWD turbo w about 150,000 miles that needs the throttle body cleaned. It's my first modern Volvo. Online sources say cleaning the XC70 throttle body is easy, and takes a professional 30 - 60 minutes. My Volvo mechanic says the engine or something has to be moved from below, and it's 2 or more hours to clean. Can you folks add any insight?

I previously would take my mechanics word as gospel, but he's swamped and its ... complicated. Nobody is perfect. I guess the Volvo 'by the book' method might be longer, but some might access it from above? Just guessing. (A 2- or 3-hour job can get expensive in the big city. FWIW, AI says its not complicated, but garbage in ....) I might prefer to take it to a closer mechanic who deals with European cars who can get me in quicker.

Thank you in advance.

 

1. Why or what makes you think "the throttle body needs to be cleaned"? (I trust this is your diagnoses and you are seeking someone to perform what you think will solve your problem)
2. On your car the throttle is mounted upside down on the bottom of the intake manifold. Take a look - does that look easy to get to? On the non turbo cars the throttle (in that year range) is on top and exposed.
3. To get to the throttle, you remove the charge air pipe from the intercooler to the throttle - then you can touch it. You can't really see into it without a mirror. And there's not enough space for two hands with a can of carb cleaner, a rag, and be able hold the plate open - so you remove the throttle housing from the engine. Then you can clean it and reinstall. If your throttle plate is dirty, and preventing the correct amount of air in, therefore making the idle speed low - the ECU simply tells the throttle to open further. Cleaning is not as crucial in the same way it was with earlier Volvos.

Again - why do you want your throttle cleaned?

Those bosch throttles do have problems - a known fault is connections in the wiring from the throttle to the ECU. Volvo sells replacement wiring for that. (connection problems were discovered a few years after those cars were on the road and many throttle bodies have mistakenly been replaced for electrical connection problems)

Also the throttle position switch in those is mechanical and can wear out.

 

Thank you for your detailed reply.

1. My Volvo mechanic w 30 years experience recommended this as my next 'to do' service. It struggles while idling, and in reverse.

The past six months I had some ignition issues. Replaced the Fuel Control module and battery, then a few months later the starter went out. When some intermittent non-start issues appeared, I asked my mechanic to replace the Position Control Sensor and a relay fuse. It still runs rough at idle, and I frequently put it in Park at stoplights to give it peddle and prevent it from stalling.

Last night I made a couple of short trips, and then I would crank it, it would start to catch, and stall. This happened 3 times before I gave it an hour break, and got it to start.

Rough idling and rough Reverse are supposedly classic signs of a dirty throttle body. It goes great down the freeway (though I also currently have an intermittent ABS issue). Cleaning the throttle body is supposedly a typical maintenance issue every couple of years.

AI was incorrect saying this was an easy straightforward job.

2. Is this a 2- or 3-hour job for a professional Volvo mechanic?

Thank you again for the helpful information.

 

1. Any fuel trim codes stored? I would look for air leaks - that is unmetered air getting into the engine. Any air leaks between the air mass meter and the combustion chamber will cause the mixture to be incorrect worse at lower rpms. And has someone checked long and short term fuel trims? Any air leaks will cause those to be off.
2. Yes. At my shop cleaning the throttle body and resetting basic idle and throttle switch was part of every 30k service (on the ~1971 - 1998 fuel injected cars. Prior to that carbs were cleaned and adjusted). That ended in 1999 with the drive by wire throttles. They simply did not seem to get as dirty. The earlier cars (240/740/940/850/s70) dumped most of the PCV fumes into the intake right before the throttle plate. So oil and carbon deposits built up pretty quickly. In later cars the pcv "exhaust" was moved further away from the throttle plate.
3. Sure - I would charge at least 2 hours to remove, clean, and replace one of those throttle modules. (however I can't recall ever doing a simple cleaning for anyone to solve a rough idle problem) There should be some additional diagnostic time also to verify that fuel trims are ok, and the other parameters that can make an engine "run rough at idle" are ok. What's the compression? What's the fuel pressure? What's the fuel pump duty cycle? (if that applies to your fuel system) What brand and how old are the spark plugs?