Code 71. Replaced vacuum module and cleaned egr valve. Code persists.

[CrazyPete]

Good day folks. I have an 1995 OBD-I corolla 1.8 auto throwing a code 71.

As my first piece of diagnosis, I reset the code and it came back. Ok, repair is in order.

Next, I unbolted the egr valve and verified that it is not stuck. Sucked on the vacuum line and it does in fact wiggle under mouth pressure. Ceaned it a bit, sprayed some carb cleaner inside and reinstalled. Code came back.

Bought the inline vacuum module from toyota and installed it. Code came back.

Now I am stumped. The dealer said that those are the only 2 components involved in the system. All the hoses look fine in the area.

What should I be looking at next?

Thanks in advance for your help!

Pete

[toyomoho]

Do know this car but best GUESS the two components are the EGR valve and modulator. The modulator controls the EGR valve (looks like a can with a diaphragm inside). Follow the rubber hoses from the EGR valve to the modulator. There might also be a VSV (electric solenoid control valve) between the modulator and EGR valve to control EGR vacuum on/off.

Check to see if you have these components. If so the check to see if the modulator is receiving vacuum from the throttle body, the VSV valve is working (turns on and off by 12V DC), the metal line running between the EGR and modulator the passes exhaust is not plugged. The modulator or VSV valve can go bad.

If you have a vacuum hand pump you can bypass the modulator and apply vacuum directly to the EGR with engine running. The engine should start to die when vacuum is applied and exhaust gases are drawn in. Then test up the system a little further.

The EGR may also have a temp sensor that can go bad.

Best guess, hope this helps.

[CrazyPete]

You know....I havent played with the modulator yet....

I'm going to carb cleaner it tonight and see if this cures the issue.