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valmiki

2010 Gen3 Prius holding revs (not cold start!)

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Hello folks,

My 2010 Gen3 Prius is now on 108k. Over the last few days I've noticed a tendency for the engine to hold revs, even when I've taken my foot off the accelerator, for maybe a second or so. It would then drop down, almost as if the signal to drop the revs is taking time to work it's way to the engine! This is when the engine is up to temp, and the Battery has way more than the two bars, so it's not related to those common scenarios. It also doesn't happen all the time, just every now and then, usually the late afternoons. With the age and the mileage of the car, I'm wondering whether there's something on the way out? The hot weather we've been having could be a cause (but then why would it hold revs, surely that would make the engine hotter?). I have a scanguage connected to the obd port, so I can always see the rpm, and if the sound of the engine wasn't enough (and it is very noticeable to me at least!), the rpm indicator indeed tells the same story. To deepen the mystery, there's no fault codes either.

It's a funny one 🤷‍♂️ Just wondering has anyone come across anything similar with theirs? I'm reluctant to ask the local dealer to take a look, they want £80+vat just to diagnose :rolleyes:

Thanks

valmiki

 

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Check the hybrid Battery cooling fan, if the fan is clogged / blocked the Hybrid Battery can start to get too hot and possibly overheat ( will then give a fault code ) symptoms of this are:

Engine running longer/harder when driving / idling 

Reduction is fuel economy

Remove the RHR boot trims, pull the fan out and clean the crud out, refit then add the intake filter (G92DH-47010) to prevent further blockages ( clean filter every 10k )

 

 

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Thanks for this. Don't really want to start dis-assembling the rear seat, it's a bit out of my skill set lol. I'll read up on the process a bit more, I've seen the youtube videos.

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I may be stating the obvious here but have you checked the floor mat is not obstructing the pedal ?

 

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18 minutes ago, kithmo said:

I may be stating the obvious here but have you checked the floor mat is not obstructing the pedal ?

 

🤣 First thing I checked!

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Hi, It make sense to me to be a throttle body that needs cleaning the most plus egr and cooler. You have exactly the same symptoms as any other petrol engine car. Always trouble comes in hot weather. At you mileage and if never been done this procedure it’s the right  time to do it. Start with throttle body and the sensor mounted on it, than after you can do the other things. YouTube plenty of videos how to. 

Good luck

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How old is the 12V Battery? They can cause weird symptoms when they're on the way out, including the ICE running longer than normal, increased fuel consumption, etc. Maybe check the 12V voltage after the car's been parked up after a while and see if it's particularly low.

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Thanks to everyone for chipping in.

The 12v Battery was replaced via the dealers about 3 years ago, and I keep an eye on it on the scanguage, so I'm pretty sure that's not the cause.

I may wait for cooler weather, and then see if the problem still occurs, in which case it is almost definitely the hybrid Battery heating up or the throttle body.

The car is reaching that age where one wonders is it worth searching out a good independent for those extra maintenance bits and pieces, but then hybrid systems still spook the locals a bit (especially here in Swansea).

Also, something I found recently when trying to find somewhere to get the aircon serviced/topped up, none of the major independents eg. ATS/KwikFit/Halfords want to touch hybrids any more! No idea why, Kwikfit did mine about 5 years ago?!

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The aircon is a bit unusual as it doesn't use a mechanical belt-driven compressor like most cars, so requires a different lubricant in with the refrigerant. I wouldn't trust somewhere like Kwik Fit or Halfords to use the correct stuff anyway. Might be best off going to a Toyota dealer for that at least.

Also, if you get an OBD-2 scanner that can be connected to your phone (bluetooth or whatever), then there are apps like Dr. Prius and Hybrid Assistant that can be used to test your traction batteries. Hybrid Assistant is also good for monitoring various temperatures (ICE, inverter, Battery), seeing the Battery fan status, and other things.

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  • Club Hybrid Poll

  • 219 Hybrid Reliability

    1. 1. If you were to consider buying a Hybrid model over 5 years old, would you be worried about the reliability of the Hybrid system?


      • Not really as Hybrid systems are always reliable
      • Not if it had a Manufacturers Warranty on the Hybrid system
      • I would not buy a Hybrid model over 5 years old