Code71

I have a '95 4runner with 120K and an intermittent problem causing a check engine light. Every time I check it, it comes up as code 71. I have been pulling the fuse to reset the ECU but I have had enough of that.

Background: Dealer replaced the short block about 10K ago. Ever since, I go about 2-3 weeks of every day mixed driving (city/highway) with no problem and then the check engine light will come on. A repair shop diagnosed the problem as a bad EGR valve which they replaced. Still have the problem. Modulator and vacuum seem to check out.

I suspect the mechanic didn't do a good job as I found he installed the TPS wrong (engine ran poor, timing advance worked backwards). Could this be a grounding/shielding problem? If so, how do I check it?

Any suggestions would be appreciated.

MTL_4runner

Seems to me I have heard of this problem before. I can't remember exactly hat the solution was but the person had replaced the EGR just like you did and it did not fix it. Do a search and see what you turn up for it.

The garage usually just does the obvious (parts replacement per the code gotten):
http://www.off-road.com/toyota/tech/codes/index.html

mtnfreak

Don't know about the '95s, but in earlier trucks, code71 only applies to vehicles with California emissions. No one else as the gas temp sensor. I kept getting that code and it didn't go away until I replaced them O2 sensor.

Rayday81

Code 71 is the code for "System too lean" I believe. Since you already replaced the EGR, most likely the problem is a bad O2 sensor. If you've never replaced this then I could definately see this as the problem. An O2 sensor is easy to replace yourself so don't take it to a mechanic. I would check the voltage on it first to make sure it is bad though. Check the tech writups b/c I think someone has done a writeup on this.
-Ray

95_4X4Runner

I was getting a code 71 on my 95 after I installed headers, and it went away after I cleaned the connector out with some de-oxit.

Search for "code 71", my original post is at the bottom of the results.

Code71

I finally replaced my O2 sensor with a new one from Bosch and then reset the computer. However, I am still getting a Check Engine light for Code 71. Dealer wants way too much (about $250) for the EGR Temp Sensor.

Does anyone have any more suggestions?

ChickenLover

I had the egr valve code coming up on my runner as well. It happened after the stealership replaced my starter. (?) . I too got sick of reseting the computer so I just took the check engine light bulb out.
Probably not too smart, but at least now I'm not annoyed by the damn light!

bike4miles

That's exactly what my situation is. I have cali emissions and was told I had to replace that sensor located near the egr valve (only on Cali toyotas) to make it go off. It's been 2 years now and I still havn't gotten around to it since it costs $150 This summer...

bike4miles

I have been told that the engine doesn't run as efficently when the check engine light is on so it might be in your best intrest to find the cause. Thats the only reason I'm going to throw down $150 for a sensor the size of my little finger.

abalagtas

How did you check out the EGR VAC Modulator? I initially cleaned the little filter disk with carb cleaner and the code went away...w/o reseting the ECU. About a 3 month later, it came back. I replaced the whole Modulator and the code hasn't returned.

rbmc

I recently had the same problem on my 94' 4Runner, I got he the check engine light.(code 7-1) When it got hot out one day a couple weeks ago the check engine light came on. Fortunately for me my next door neighbor works at the local Toyota dealer, he came over with his vacuum guage, hooked it up and had it diagnosed in about 20 seconds. He told me the EGR modulator failed, he said that it had a hole or maybe a tear in the diaphragm. After prying it open and looking at it, sure enough it had a 1/4" tear in the diaphragm. I asked him what made it fail, he said "age of it, time and some bungholio spraying carb spray into the ports". So I hit him up for another one, (his price of course) problem solved .

RBMC