General Maintenance

If you haven't ever had the EGR valve and cooler cleaned in 220k miles, it's highly likely you should do that too. One way to get a sense of how clogged it is would be to use a cheap Bluetooth OBD tool ($15) and a free app to check the EGR monitor. Information here on how to test and here on how to interpret the results. Note that you should STILL clean in the intake manifold and its tiny EGR ports because the EGR monitor can't tell if one port is blocked and several of us believe one blocked port is what leads to head gasket failures. Read the last couple pages of that second link for more info.

All that said, cleaning the EGR system and intake manifold thoroughly (possibly just installing a new or used-but-cleaned EGR cooler) would likely be $600-800 for a mechanic due to the labor. And if they haven't done it before, there's not promise they'll do it right (especially the intake manifold tiny EGR port cleaning).

Here's what I did: I cleaned the intake manifold, throttle body, MAF, MAP, and EGR pipe at 158k miles and checked the EGR monitor as described above. My test value was 16kPa, which I think is OK. It was my first time touching any of those components and it took me a total of maybe 4 hours (not including time where the manifold was soaking in degreaser). If you're at all DIY-capable, it's worth considering doing. I'll still clean the EGR valve and cooler this year, but I'm feeling less urgent about it.

 

You will need the egr cooler cleaned or replaced if it has not been cleaned before....it will be clogged full.

SM-G960U ?

 

Most likely your egr system is not totally clogged until you get a
P0401 Code: Exhaust Gas Recirculation (EGR) Flow Insufficient Detected. But it will certainly be almost there in any case.

Its not a simple job to remove the cooler, clean it or put it back in. Many mechanics will underestimate the work thinking its similar to other Toyotas. It can take many hours just to clean the cooler, a totally flawed design Toyota did not have in the gen2s and completely redesigned in the gen4.

As a result dealers won't clean them, they will quote new parts which runs the bill to $800 and above.

 

With 220k? Exhaust Gas Recirculation AND intake need immediate attention. More info:

Bad Flywheel | PriusChat

How’s the engine coolant level, stable?

 

Don't discourage another data point!

If OP reported that the test value was above 15kPa or so, I'd argue the need isn't immediate based on everything I've learned here. But what's the definition of immediate? Within the next 1,000 miles? Before the next time they drive the car at all?

 

As soon as reasonably possible.

 

Not sure if @TMR-JWAP has progressed into the Gen3 space yet or not, but he has vast experience with the Gen2 sector.

Good luck with the maintenance and keep us posted .