Excessive EGR Flow 1999 Tacoma 2.4L

I was getting an excessive EGR Flow error code, so changed out the EGR Valve and am still getting the same excessive flow error. I was told that an aftermarket, may still get the error. Any ideas on the way to go about getting this error code to turn off and pass smog?'

These are pic of the old EGR Valve that was getting the error. The new one looks exactly the same - doesn't this look like and OEM part? Not even sure... Sorry, new to the fixin car world...Thanks in advance - Moshdog

 

It could also be the egr modulator, which is a lot cheaper than the egr valve. The modulator is the black disk looking thing with all the small vacuum lines going to it.

 

Also had that on my 04. Had to take my intake apart and did some cleaning of the port.

 

Shoot.
Just had this on my wife's 99 4runner also.
The big black box as she calls it was leaking and threw the same code. I'll try and find the link to test and post it.
I think it's in the drivers side fender well and hoses come from egr to it. Its tge charcoal pot I guess. They leak around the bottom seam just epoxy it back up and
But check it first.

 

Is it po402 code?

 

That’s the charcoal canister. It’s in the engine bay on v6s and under the bed on 4 cyls (at least for ‘01-‘04)

 

Not exactly correct about locations. 95-00 it's in the engine bay, 01-04 under the bed by the gas tank. Engine doesn't really matter.

 

NZbrock) I cleaned the filter in the modulator and then put it back on. Also bought one that was cheaper and tried that, but I read that it should be the same. So I am waiting before buying a 50.00 new modulator for no reason. I could just try that and hope for the best.

Whitebutler) If the intake was clogged would that still trigger an excessive flow? I would think it would be the opposite, so I have opted against pulling the intake off for now. Also, I checked the switch coming from the charcoal canister and it was working and out it back on / 401 code.

Thanks all for helping out, still not sure what it could be...

 

Not sure about your model but the PCV valve and VSV egr selnoid play a part in EGR as does modulator and vacuum hose leaks.

 

I'm assuming this is P0402: Exhaust Gas Recirculation Flow Excessive Detected
These are the possible causes:
EGR valve stuck open
EGR VSV open malfunction
Open in VSV circuit for EGR
Short in EGR gas temp. sensor circuit
ECM

I suggest testing the EGR temp sensor since that's an easy one (DI-95 in attached).
Should read 2.5k Ohm or more between the terminals while cold.
Short would read 200 or less Ohm.
I have attached the procedure for diagnosing P0402 on the 3RZ and 2RZ

Also, the VSV for EGR is located in the middle of the intake runners and is a little tricky to reach. It's the little green solenoid thats mounted on the bottom runners. If this is bad it can cause problems with the EGR not functioning correctly.

 

NZBrock - Yes, it is the PO402 code. Thank you all for your advise.

 

Opposite

 

I had the same code and it was a bad VSV.

 

Put a vacuum gauge on the little hose that feeds vacuum to the egr valve and see if its got vacuum all the time, it shouldnt. Egr should only open up on accel and cruise. If there is constant vacuum available on the hose then the vsv may be stuck open. Are the vacuum lines routed properly?

Is the egr valve hot to the touch? Like quickly, after the engine has only been running for a couple minutes? Thats another sign that its opening too much and flowing exhaust when it shouldnt

 

Turns out it was a bad sensor - so check engine light is officially off!! Thanks All!

Now the computer is not clearing so still cannot smog.

Have done a reset with my computer reader, manual reset = (touching the battery cables together) and still nothing. Going to keep trying.

Any suggestions would be appreciated...

 

Disconnect the neg terminal for exactly five minutes, make sure all accessories are off, start and let run five. Turn off. Works for me every time. I have tried many methods, good luck

 

Great to hear that the new EGR temperature sensor took care of that for you.
Sounds like you need to get the OBD2 readiness monitors set. Read up on the drive cycle to get OBD2 testing completed. Typically normal daily driving will have the conditions needed to get the OBD2 monitors completed, but not always.

 

Like cruiserguy said, the ready test takes 100 to 250 mi with multiple start stops plus overnight and temp variables as well as 1/2 tank of gas for EVAP cycle. Its always best to let CELs clear themselves rather than Battery disconnect or OBD11 clearing codes.

 

Engine was only getting to 129 F so I checked the thermostat and previous owner had left open. Changed out to 185F Thermostat and checking again in a few days. See how that goes...