QuestionI have been talking with you for the past several months and the last thing you told me to do was try a known good computer which I did and I received the same code of 71. Is there anything else that you can think of? I really want to thank you for all of your help so far.
Chris
AnswerYes just a couple,there may be a problem with the wiring, the engine wire loom has a few soldered splice points inside the insulation, they can get corroded and create bad connections which mean high resistance and a possible short circuit. Check the wire harness underneath and make sure the harness has not touched the hot exhaust anywhere, check the O2 sensor connectors and the wiring, you may have to cut the harness covering open, then check in the engine compartment from the firewall foreward, open it and check for any signs of corrosion on the splice points.
This is not common but I have seen it.
You can do resistance tests but this is also time consuming and you will need a wiring diagram and a shop manual and a multimeter and the ability to interpret the wiring diagrams.
The other one may be that there is a small vacuum leak at one of the vacuum hoses on the EGR system, I once worked on a corolla and had the 71 code and replaced some parts and cleaned the inside manifold passage and the system tested perfect but it came back twice after that with the same code again, finally I found a small pinhole in the vacuum line at the EGR modulator, replaced the vacuum hoses and it was fixed.
I probably asked this before so bear with me and let me know if any of this is incorrect:
The egr valve was replaced
the egr modulator valve
the egr vsv
the egr temp sensor(by the way check it's connector)
the intake chamber passage was cleaned
the engine stumbles and either dies or almost does when vacuum is directly applied to the egr valve
There is vacuum at both the P and Q ports when the throttle is opened
There is exhaust back pressure to the modulator valve
Waiting to hear back from you.
