Engine light on

so do you think we should all be cleaning it at 24,000 miles?

 

A thorough cleaning of the whole system is kinda daunting; getting at the EGR valve, and then the cooler unit behind it (with connected coolant hoses), and the pipe connecting to the exhaust behind that. At the front end getting inside the intake manifold for a look is no easy task. Maybe Christian will comment on that.

But, just pulling off that one, relatively easy access pipe at the front of the EGR valve gives you some idea of it's state. I say relatively easy, 'cause the bolts on the mainifold end flange are obscured by a plastic connector, a really brilliant design, not.

It's an hour in the garage, and you'll have your answer.

 

I would wait for the DTC to be logged, before taking action. It's not the end of the world if the EGR is slightly less effective, that just means less exhaust gas is getting routed back into the intake manifold.

The purpose of EGR is that by introducing some exhaust gas into the intake, combustion chamber temperatures are reduced because the presence of the exhaust gas dampens the ability of the fuel/air mixture to ignite. That reduces the production of nitrogen oxides in the exhaust.

 

thanks guys. is this more or less likely in an engine that is infrequently used, like the pip?

 

Funny, I was just thinking of your case: less engine use would likely mean less clogging.

Here's Christian's thread on the subject:

Prius 2010 Engine Knock - Manifold Issue | PriusChat

 

i guess my concern is the amount of times the engine comes on just to warm up, and never gets any real workout.

 

Geez, Alzheimer's is setting in; I hardly remember these threads. Christian's is more intake manifold related, and there's this, a fishing expedition of the EGR:

Prius III engine knocking at high torque low RPM (solved) | PriusChat

 

Did you miss a few zeros? Now I'm more confused than usual, lol.

 

Prius erg p4041
Don't replace the egg valve! I figured out how to fix it.
This is very simple.
Step by step;
pull off the plastic cover on top of the engine, just lift up.
Look on the right top side of the engine and locate the erg valve, black round with a wire connection in plain view, and two Phillips screws. Unscrew the two screws and pull the black cover off. There is a black magnet, with a bearing, unscrew that. You will see the threaded shaft it came off of. All you have to do is slip a washer over that shaft, and screw the magnet back on, then reassemble. You'll have to go through three start cycles before it will reset.
The flow restriction is caused by the pin, inside the magnet, wearing down, thus preventing the valve to open enough. With the washer, this extends the throw of the valve, and solves the problem.
Thanks to all for posting, but I found this to work, and want to share. Good luck.

 

Correct I agree, and I am sure Toyota is aware of the problem with EGR and Manifold bot don't offer a recall. I have to clean up my 6 year old Prius every 15.000 km.

Posted via the PriusChat mobile app.

 

Prius egr code p0401
Don't replace the egg valve! I figured out how to fix it.
This is very simple.
Step by step;
pull off the plastic cover on top of the engine, just lift up.
Look on the right top side of the engine and locate the erg valve, black round with a wire connection in plain view, and two Phillips screws. Unscrew the two screws and pull the black cover off. There is a black magnet, with a bearing, unscrew that. You will see the threaded shaft it came off of. All you have to do is slip a washer over that shaft, and screw the magnet back on, then reassemble. You'll have to go through three start cycles before it will reset.
The flow restriction is caused by the pin, inside the magnet, wearing down, thus preventing the valve to open enough. With the washer, this extends the throw of the valve, and solves the problem.
Thanks to all for posting, but I found this to work, and want to share. Good luck.