Not just another p0401.. PICS!

^ I was wondering about that. There's some mention of more "cooling" of the EGR too, not sure of the significance. Funny how Toyota's completely mum about so much on the 2016, but going into such detail on some things. I'd like to be a fly-on-the-wall when they're discussing what to disclose to the public, and why.

 

All

Chevron 67740 Techron Concentrate Plus Fuel System Cleaner - 12 oz every 3 month then we should not have this problem

 

Maybe an ultrasound cleaner?

 

A replacement part is more effective and sort of economic / time involved

 

From the Repair Manual, section covering the EGR components. The presentation as usual is extremely terse and cryptic. See you need E8 Torx socket.

 

Any idea of the service center charge?

Bob Wilson

 

good idea. i also suspect a pressure washer should strip the carbon. the trick is not to hold the part in your hands.

 

Doubt it.

 

I think it should have read ultrasonic, lol.

 

So once the EGR system is completely clogged, how's the Prius going to fare in pollution tests? Maybe it'll take a VW style scandal to get them off their duffs?

 

Good question! Based on the trouble code, or actual testing? Not many jurisdictions require physical testing for NOx under realistic load conditions, as far as I know.

 

Really? How do you propose to introduce it into the hot EGR flow between the engine and that heat exchanger?

 

Yes, really, if you do this every 3 month the the entitle fuel system will be clean and you will not have any Carbon deposit. But now it too late just replace the new part and start use the good gasoline

 

Hot exhaust gases with carbon content are being run through a radiator. I think this contraption would be clogging up regardless of the gasoline or additives.

Toyota's design is hard to get at, hooked up to 3 coolant hoses, looks to be impossible to open up for cleaning, costs about $250 to replace (new), and another $250 for the valve just downstream.

 

what kind of gas did you use? there could be a connection with gas quality as GrumpyCabbie had a failure of his EGR at 70,000+ miles of cheap fuel.

 

Sometimes it's like talking to a wall trying to make some people understand how the EGR system works and that fuel additives don't reach that part of the system.

I agree with new parts and not trying to clean hard to reach parts in the cooling unit. There is a complete all inclusive EGR system on EBay for about $160. It came off a 2014 Prius. It may be worth buying for use later. You should take a look.

 

Just for discussion, here's an exploded view of the components, from the Repair Manual:


(see there's actually four coolant hoses connecting)

The EGR assembly has sub-components, I've marked A and B. They are respectively:

VALVE ASSY, EGR p/n: 25620-37110
PIPE SUB-ASSY, EGR W/COOLER p/n: 25601-37010

Part numbers and descriptions from:

2010 Toyota Prius Exhaust Gas Recirculation System

Regarding gas choices: I've only removed the EGR Pipe Assembly, around maybe 45,000 kms. It had noticeable build-up, not bad, but certainly something being deposited:


(The picture's a little deceptive: the orifice flares at the end, so it's not as bad as it looks. But definitely something deposited. And this is downstream, past the radiator and the valve.)

I'm using Chevron regular, with very rare exceptions.

 

My understanding is that when the EGR system is blocked it will throw a code, but the car will still drive (i.e. It will not cause any damage to drive it that way). If this is the case, I think I will just leave it be until it codes, and then buy new parts to fix it.

What's your understanding on the drivability issue?

 

There are some ramifications to driving with clogged EGR. I think, and gotta say this is just from what I'm reading.

First, the car's polluting, more than it's spec, nitrogen something? And you'll be driving with a constant check engine light, so it'll tend to get ignored, and there could be other, unrelated codes, besides P0401 "joining the party", which will get ignored.

As far as driveability, mpg, I believe there is some impact. I did just a little searching yesterday, noted a few links. The YouTube video is a guy working on a non-Prius vehicle, but it's interesting. I like the guy's demeanor, couldn't go far wrong thinking like him. Here's the links:

Overview of EGR, benefits, issues:

The Exhaust Gas Recirculation Valve EGR FAQ | Hypermiling | Fuel saving Tips | Industry News | Forum

Interesting video, guy diving in on an EGR issue. Not Prius, but worth a watch:

Priuschat question regarding p0401, and TSB for EGR replacment and warranty extension (Californial only) posted:

Anyone got check engine light P0401 EGR shows up in every few weeks... | PriusChat

Good (EBay) picture of the complete EGR assembly:

2010 11 12 13 Toyota Prius EGR Valve 25620 37110 Adapter 25601 37010 | eBay