Alex 400

so my Check engine light kicked on and when i pulled the code, it was code 71. it also said that it was a california car code. but my truck was bought here in washington, as far as i know. for those that have had this code, what was turned up being wrong?

thanks guys!

thook

I think CA vehicles are the only ones with gas temp. sensors, so see if yours has one. It would be on the side of the EGR valve body. If not, you should have a bimetal valve that controls the temperature at which valve is allowed to open. On the back of the upper intake manifold, I believe. It's been awhile since I've had to look at my 3.0 to fix anything, but I believe that's where it is.

The bimetal valve will have two, small vac lines going to it and a vent cap.....no electricals.

anotherjeff

Deja Vu!!

Alex, you posted the same question one year ago!!
https://www.yotatech.com/forums/f116...e-71-a-119293/

Has your CEL been on for the past year?

Alex 400

i do have that temp sensor on the side of the EGR valve. if one of those was to crap out, would that trip the code?

4Crawler

iTrader: (3)

Yes, the ECU logic is that if it commands the EGR valve to open, after a period of time, the temp. sensor should indicate a temperature inside the EGR valve above some minimum value to tell the ECU that hot exhaust gas is indeed flowing through the valve. If not, the ECU assumes with the sensor or the valve is not working.

Alex 400

no actually! it turned off for about 7 months then the light would come on everyonce and a while, but it was never on long enough for me to pull the code, i had a little time so i just ran out and pulled the code because the light was on. the reason why i am trying to jump on it now because i am tryign to get the truck all ship shape before heading off to college. got a few long drives ahead.

Alex 400

ok so i did test the egr valve with a vacuum pump and the motor stumbled when i opened the valve, so the valve checks out. would you think that its the temp sensor?

thook

I would.

Alex 400

alright, thanks!

thook

It's easy to test.

This is the FSM procedure, but you can test it while on the vehicle.
http://personal.utulsa.edu/~nathan-b...00egrgaste.pdf

You can test either in ohms or voltage. In ohms, the resistance should start high and go lower as the temp rises. In voltage, it will be opposite. The volts should start low and rise.

l3fty

Don't forget to blow/clean out the EGR vacuum modulator filter. I just had the same code right before a 3 hour trip. Blew out the filter and checked the one way valve off the VSV, (I think it may have been stuck) and the CEL hasn't come back. I always start with the easy stuff first.

thook

Right....good point. I forget about those modulators because I no longer have an EGR! (don't ask....)

Alex 400

alright thanks, i will look into that.

well there is no drivability issues, just the annoying light. whenever a CEL comes up, i pull the code just to make sure it is just the egr and not something else.

anotherjeff

uhhh....... Do you realize that codes are stored? In fact, stored until cleared?

anotherjeff

uhhh....... Do you realize that codes are stored? In fact, stored until cleared?

toyota_mdt_tech

EGR isnt working. Is there a sensor screwed into the EGR valve? IF so, this isnt seeing heat. Usually, its the vacumm hoses in the wrong place or knocked off. Did someone poke around in there?

yotaman8819

i have had a code 71 for 3 years and it wont go away

Alex 400

yes there is a sensor screwed into the side. I did "poke around" in there to replace my fuel pulsation dampner, in which i had to remove everything. I marked a labled all vacuum hoses to make sure i put them back on in the right places. and i also checked to make sure all of the hoses were in the right place as well. but this had come up even before then, so i don't know...

Alex 400

yes i do know that and i have cleared the code a few times, but sometimes it comes on and stays on for a week or so and then goes off or sometimes it will come on on the freeway and then 20 miles later, sometimes sooner and sometimes just getting off the freeway. drivibility does no change at all whether it's on or off.

4Crawler

iTrader: (3)

The Factory Service Manual has the EGR testing procedures in it. See if the EGR is opening by manually applying vacuum at idle, should make engine run rough or even kill the engine. The EGR may also be caked with carbon inside, coating the temp sender so that it does not get hot enough to satisfy the ECU.

A buddy of mine had that same problem and ended up getting a new EGR valve and swapping out the old one ('94 pickup). Since it needed to get smogged (in CA), he could not have the CEL coming on at random.