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Mike, Mechanic
Category: Volvo
Satisfied Customers: 39198
Experience:  Tech Expert
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I have had serious power reduction issues -and my 08 reg

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I have had serious power reduction issues -and my 08 reg s60 auto has had two replacement Throttle boxes but to no avail - I am taking the car back to the Volvo Service Garage at Chigwell on Monday - they will check the diagnostics clear the error list and away I will drive -but a week later the dangerous power reduction will again kick in -this is exasperating and dangerous -what can the problem be and why cannot it be corrected.
Is there Brake Throttle Override on this car- a friend who knows more thyan I do has suggested that as the likely source of the problem
Hello and Welcome..

My name is ***** ***** Im happy to help / advise..

I need to just ask a couple of things,...

When did the problem start exactly - can you give me some background?

Can you determine if it started around the time anything was done to the car / work etc / parts fitted and so on -- ?

Do you have a fault light on when you have this issue?

Do you have the fault codes ?

What mileage is on the car?

What exactly has been done / tried so far -- ? ( other than just deleting the codes and sending you away ) ?

Please also give me the cars Full reg number - so that I can determine its exact engine management system -

Please just type your reply here - When I receive it, I will get back to you asap thereafter / later today...

Best Rgds, MIKE......................................
Customer: replied 3 years ago.

Greetings Mike,

This problem first occurred abot 18 months ago - visited Volvo garage -they cleared the diagnostic errors and no problem for another month or so - then recurred- same procedure - suggested battery needed replacement -this was carried out and shortly thereafter problem recurs- new Electronic Throttle Modulator fitted - in August last year - but problem recurs August this year and new Throttle Box again fitted - and that was only 2 weeks ago. Now the problem has re- emerged - for instance this morning start up 9.30 - "reduced engine power" script appears after a few miles and also the amber warning icon - but car performed well for 7 miles and then developed power loss -just made it, unevenly chugging along and currently parked outside office.I suspect it will behave well long enough to get me home tonight but I could be wrong!! Worrying and also when in this strange mode if for instance I have stopped at a pedestrian crossing I have to take the precaution of using both handbrake and foot brake - in this situation the footbrake requires more pressure than normal -thus the additional p[recautionary use of the handbrake.

Mileage is 37,000 miles

Reg is AC08YAV

I do not have the fault codes immediatelt to hand as they are at home with my recent service sheet,

Hope this is reasonably informative.

Best regards,


Hello there Patrick -

Thank you for your reply and further info - thats good.

Patrick - with the info you have provided along with the actual symptoms you describe - and knowing these issues / vehicles , I'm convinced I know what your issue is here.

Quite why the dealer has not picked up on it I dont know - though I can does just happen sometimes... Really, I would advise to either use a different dealer or a local known good garage... you would save a lot of money with the latter too if you could...

Back to the issue in hand, there is a known problem with the VVT valves on this engine...that will cause exactly as you have. In fact, Volvo did issue a fix bulletin for this fault - I will outline it as follows for you :

  • Lack of power.
  • Sometimes Engine pinking.
  • Trouble codes stored in engine control module (ECM) fault memory
  • Variable valve timing (VVT) solenoid piston sticking due to metal swarf contamination.
DescriptionPart numberQuantity
  • Remove VVT assembly from engine.
  • Disassemble and thoroughly clean all components.
  • Ensure all oil passage ways are clear.
  • Check operation of solenoid by applying a power source.
  • Reassembly and refit.
  • Erase trouble codes.
Most any local good small type garage can deal with this for you Patrick - just check if you choose to use one, that one, they have the test / diagnostic equipment to deal with your car - and that two, they would know what to do as per the above... and that as I say, will save you a lot of time , money etc and get this sorted for you from what you have outlined.

Im very pleased to have helped you - Do let me know if you need anything more --

*** Meanwhile - - >>>> Please do click on the "OK/ Excellent ratings" for me - Thank you in advance for that...

You can and are most welcome to get back to me anytime you might need - clicking the OK ratings does not close you out at all..

Kind Rgds, MIKE.
Mike and other Volvo Specialists are ready to help you
Customer: replied 3 years ago.

Many thanks Mike I've always suspected something "physical" rather than just computer gremlins- I'll cancel my appt with Volvo garage and try a local entity,


ps would you still want me to send the fault codes?

Hi there Patrick..

Thats fine - no problem at all..

You can send the codes by all means if you wish and I'll take a look... but again - Im sure thats what your issue is there...with what you have outlined..

So I dont mind either way..

Can I just ask that you please click on the OK ratings for me at this point Patrick - thank you kindly... and should you need anything else - just come back to me here after.. clicking the OK ratings doesn't close you out at all Thank you again..

Best Rgds, MIKE.