Hello,
My 22re has been getting a CEL Code 25 for a while now.
I'm having troubles figuring it out.
I've check the service manual and looked into a few things.
- Engine ground bolt is not loose.
- Fuel line pressure, (run about a quart of injector cleaner in it)
- Oxygen sensor (metered it out, perfect condition)
- Engine coolant temp sensor (metered, just fine)

The check engine light goes out only when it's raining, oddly enough.

I'm thinking it's the Volume Airflow meter, seeing as when it rains, the moisture displaces the oxygen, therefore richening the mixture and countering the lean mixture conditions.

Anyone got any ideas?
Gotta look into setting the AFM.

 

You might check the injector connectors (or better yet, use the small-rubber-hose stethoscope and listening for them clicking when running). If you have an iffy connector, that injector won't open and you may end up lean. When it rains, a little bit of moisture gets in the connector and makes it "good."

I am curious that the O2 sensor "metered out perfect", as that is what code 25 is: "oxygen sensor output is less than 0.45 V for at least 90 secs. when oxygen sensor is warmed up".

 

The oxygen metered out perfectly, as in, within in stock specs.

As for the injectors, I've ran a quart of injector cleaner through the fuel system (not at once, of course). Not the issue, because it goes away when it rains.
So either I'm getting extra air somewhere (or a bad reading of it), or too little fuel. Aka lean mixture.
I'm ruling out the fuel because of the change when it rains.

So it basically boils down to Ignition System or Volume Air flow meter.

 

what kind of O2 sensor is this?
make sure there are no exhaust leaks also... exhaust leaks at the manifold will throw off the O2 readings