Hi Guys, I have a Toyota Prius 2016 Generation 4 (UK Model). It has done well over 300k miles as it has been used as an Uber/Taxi for most of its life. However don’t let this shock you, as it’s probably one of the most looked after & well maintained Prius’s around. Drives like it’s only done 60k. Always driven sensibly & never abused. Anyhow, it’s been 2-3 weeks now & I’ve noticed it keeps on Juddering / Jerking slightly on acceleration. It’s like a misfiring type of feeling. The engine feels as though it is shaking. This only happens when I accelerate & use the gas peddle. When it’s in EV Mode or on Hybrid mode then the juddering stops & it coasts along smoothly as it normally would. But as soon as I accelerate & the engine kicks in the whole car judders / jerks. This happens from 0mph to anything upto 50mph. I have done / checked the following: - First thing I did was replace ALL 4 spark plugs with original Toyota Spark plugs (as always). My old ones were still ok & had plenty of life in them but still I went ahead & replaced them - nothing changed ! - Then I replaced ALL 4 Ignition Coils - again all original Toyota coils - and again no change ! - I added some original Toyota Fuel Treatment into my petrol tank - no change ! Some more background information: - It has NO EML or any other lights displaying on the dashboard at any time, even whilst it judders & jerks - nothings displaying as of yet. - The oil & water levels are all fine & it’s not leaking or losing any of the above. - My fuel consumption is exactly the same - nothings been negatively affected on that side either. As I stated the car is very well looked after & maintained. Serviced every 10k-12k miles using only the most quality parts from Toyota. The Engine is run on Castrol oil as it’s the best on the market & longer lasting. The Car has ONLY ever been driven on Shell fuel - I would NEVER use any other fuel. Please help, any suggestions as to what it could be ? Andy.
Congratulations, You've isolated the issue to the engine. Now you need someone to run a proper diagnostics on engine performance, rather than throwing parts at it and hoping for the best. First off, are we speaking about miles or kilometers? If we are talking about miles, your at the end of the service life of that engine - so issues are expected, No matter how well it was serviced. If your going to attempt to repair it yourself, it's back to basics and your going to need a better scan tool. I'm pretty sure you've got pending codes that you can't see with your current scanner. At least a P0300, misfires Fuel, bad petro, clogged filter, low fuel pressure, clogged injector(s) - look at fuel trims on your scanner. compression, mechanically scored piston walls, bad valve seats - pressurize the cooling system and stick a borescope down to inspect the combustion chamber. color, consistency, scars, and how clean or dirty each cylinder is compared to each other, will give you clues to which one(s) is misfiring. ignition: Probably not ignition, since you shot the parts cannon at that, but look for wiring harness issues caused by rodents. Hope this helps...
Hi Biomed01, thanks for your in-depth reply. in answer to your question my vehicle has done well over 300,000 MILES (not kilometres). I plugged it into a diagnostic machine (snap-on) & it came up with the following fault code (as pictured): P2681-72 Engine Coolant Bypass Valve Actuator stuck open bare in mind there are no EML lights visible on the car dashboard - so this is a code the diagnostic picked up that’s not visibly showing. We opened up & checked the EGR Valve & it was bone dry & as clean as a whistle - not a spec of dirt or grease in it & not clogged up in any way shape or form. any further suggestions ? Thanks Andy
Nope, just back to basics diagnostic. Fuel compression spark What your describing is a misfire upon acceleration, which can be cause by a misalignment of any above. If it idles fine, it may be a fuel issue. Look at the fuel trims on that scanner. Also, make sure you didn't just get a bad tank of petro. Good luck
May be a problem of carbon build up on injectors or valves like actual issues on Honda direct injection engines .
Hi Guys, So as the diagnostic was showing fault code: P2681-72 - Engine Coolant Bypass Valve Actuator stuck open I decided to change this part first. It’s can also be called the: Coolant Bypass Valve The correct name for it if you have to order the part from Toyota is: valve assy flow shut (Part No. 16671 - 37010) If you see the photos of the old one compared to the new one you will know exactly why I was getting all the issues with my car. The old one was totally clogged up. I changed this & the water pump together - ALL ORIGINAL NEW TOYOTA PARTS USED & drained all the engine coolant & replaced it with Original Toyota Pink Engine Coolant. I am happy to say this how now resolved my issue. The car now drives perfectly normal & as smooth as a whistle. I have posted photos of the part & where it is located (under the EGR Valve). Thank You all for your help & advice. Happy Holidays, Seasons Greetings & All The Best. Adeel
Glad you figured that out and I'll file that one away. Since that bypass valve was stuck open, you would've had a hard time keeping the engine at minimum operating temperatures. That would lead to a lean mixture in your combustion chamber. I'm curious, did you keep up with the OEM coolant change intervals? The first is around 120K-150K miles, then every 50K miles there after. At least that's what's stated in the USA maintenance manual. The 50K mile coolant change interval thereafter, is easy to miss, because it's denoted by an asterisk. All that junk is floating around in your cooling system loop, so I would probably flush out the cooling system to avoid any future issues, because the heat exchanger passages are much smaller. Thanks again for the follow-up.....
the simple & honest answer to your question is no. I did not do the coolant changes on the necessary intervals. I know, it was a hard & tough lesson learnt. I hope I’ve not caused any more damage or unnecessary harm to the car internally (fingers crossed). When I’ve replaced the new part & the water pump just now, I did fully flush out ALL the old coolant & replace it with new pink coolant (Toyotas own). thanks
Just editorial: the Toyota USA Warranty and Maintenance Booklet says 100k miles or 10 years, whichever comes first, for engine coolant change. You were likely thinking of the spark plugs?
