P0016 error on 2006 Prius 70,000miles - is it hard to DIY replace the timing chain?

Before jumping in to replacing parts, you should do a couple things.

First is to get a copy of the factory service manual. That will have the complete procedure.

Second is to diagnose the fault. Your engine could have a timing chain fault- stretched chain, jumped chain, broken guide, etc. You would have to pull the valve cover and check cam timing per the manual.

I have seen at least one Gen2 that set a P0016 when it had a stuck VVT oil control valve. It should have set P0011 or P0012 but didn't.

Timing chain replacement is moderately advanced level work. You can do it if you pay attention to details and follow the manual exactly. That said, there are posts where someone tried and failed to do this- sometimes they could fix their mistake, sometimes they bent valves.

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At only 70k, it is unlikely that the chain/sprocket needs replacing, unless the oil was never changed.

How long have you owned this vehicle, and what kind of MPGs are you getting?

Who normally changes the oil and at what interval (with synth or dino), do you ever check the oil level yourself?

If you set a DTC P0016 then I would read these threads before spending a bunch of time/money on this vehicle.

P0016 Error Code | PriusChat and Codes P0011 and P0016 ?? | PriusChat

Try inspecting/cleaning the vvti oil control valve and filter first : VVT Oil Filter? Poor MPG'S? | PriusChat

 

Opening the valve cover is way easier than timing chain... And to think there's a problem with timing chain at only 70K miles on a Prius is like thinking you have the same problem with a regular car with less than 40K miles, because hybrid cars don't use the engine as often.

Any signs of rodents chewing on wires?

Timing chain should be a last resort once you've exhausted all the other options... First step is to see what the spark plugs look like and make sure the sensors are ok and you've cleaned throttle body, mass air flow sensor, new air filter, have a healthy 12v battery and your tires are at max PSI. I bet you do all that and you 25mpg issue will be resolved.

As in the Gen2 engine is one of the most reliable engines Toyota has ever built and there's no known problems with this car's timing chain until you're up near 400K miles and at that age it's always gonna burn lots of oil before timing chain goes bad.

 

I'm right at 300K never even heard of this code but I know it exists but just never heard of it at 300k I'm barely using any oil maybe over my 10,000 mi oil change I might add a quart and a half two at the most at 10,000 mi generally takes me 3 months oil comes out a little darker than it went in but by no means dark brown or black you can still see through it as it's running out The one NZ is a very stout engine It is almost like some of the older good engines at Toyota made like the 2/3 TC.. 3SGTE Beams etc . They make a rally version of the 1NZ etc I would be pretty shocked that you would have messed up timing set in that car I would certainly be checking the VVTI valve and any of that stuff and then try again matter of fact I've never seen anything like 25 miles per gallon when my hybrid battery was completely failed I was still driving the car the car would charge discharge charge discharge the battery in a block's time battery was toast I know that when I took it out for the new one I picked up at the dealer gave them the old one right there in the parking lot with the seriously defective hybrid battery I was still getting 37 or so miles to the gallon for weeks I can't imagine a Prius getting 28 miles to the gallon of 24 so there again if that's really accurate and that's what you're really getting something is seriously wrong but I would think for the timing to be causing that you would have like no acceleration everything would be all fubar as far as valve timing would go I mean just one tooth off in these things yields horrid running One of the VVTI doflachees not clicking back and forth or doing what it's supposed to do. I guess you could maybe get into the twenties I don't know that for a fact.

 

One thing to think about is whether that code is accurate. What device are you using to read codes? Seems very unusual for a Gen 2 to have timing chain issues at 70k miles. Anything is possible, but I would want to be 100% certain I wasn't chasing a ghost.

 

2006 Prius timing chain RR

 

I thought it could be done with the engine in place because of the three was done that way. And I've done hordes of others the same way usually faster I can't imagine pulling the engine to work on the front of it generally speaking at least not where I'm at.

 

Generally you need the special tool if there's one called for in the manual I didn't look on some of the older engines and some of the newer ones I've worked on there's a piece of metal with notches in it that you put the cams at whatever they supposed to be at drop the piece of metal on the two slots or holes and it keeps the two cams for moving while you're fitting the chain getting slack right and offering the tensioner upper what have you. The garage may have gotten that one NZ engine mixed up with something else that they've worked on used to be a lot of vehicles or engines required a tool to hold the cams I've done it a bunch of time without the tools and just get everything lined up move it back just to see here get the chain on run it up push the slack where the tensioner goes see if everything spot on and go. I would guess in the neighborhood of six to eight hours I don't know what the book pays probably about 14

 

Remove the VVT oil control valve from the cylinder head. Carefully connect two wires to the electrical terminals and briefly power it with 12V. You should a pronounced "click" and see the metal piece inside the oily end of the valve (in the slots) move some.

Look through the timing chain procedure, it will show how things should line up . At Top Dead Center on cylinder #1, the marks on both cam sprockets should point up (12:00). The colored links on the chain are only used for initial installation and likely won't line up (they will, but only once every 40 revolutions or so).

I would drain the oil into a funnel and clean plastic jug then you can reuse it.

You can do the same with the coolant if you want- you do need to drain the system because the timing cover has passages for the water pump.

Figure on at least double the amount of time that you think it will take. All the sealing surfaces need to be carefully cleaned off. Once you have the new timing parts on (be sure the chain tensioner is unlocked) and have rotated the engine 2 revolutions and rechecked alignment, then you can carefully apply a THIN bead of RTV sealer to the timing cover and refit it.

It can be very tricky to get the cover in position without smearing or dislodging some of the RTV.

Water pump, if there is any signs of seepage - pink residue around the "weep hole" behind the pulley. PCV valve, maybe spark plugs, (be careful fitting a new crank seal to the timing cover). Look at the water pump drive belt and tensioner pulley condition. Clean the throttle body bore and MAF sensor.

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