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AEM X-serie Wideband

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I have installed tow AEM X-serie Wideband gauges in my Subaru Legacy 3.0R. But they seam to read backwards except under engine braking.

What I mean with that are that the gauges show lamda 0,8 att idel and 1,3 att wot. Wen I turn the engine off the gauges shows lamda 0,9. But under engine braking the gauges go to full lean and dosen give eny reading. This is with at stock tune in the car.

Do enyone have an idea off what the problems are.


"No reading" off the end of the scale lean on decel is normal until fuel resumes near idle speed.

The rest does sound unexpected. Is the entire vehicle stock or is there an intake installed that perhaps requires a tune?

Are the gauge and sensor new? Have you verified with another wideband yet?


The only modification that I know off is a full aftermarket exhaust.

The gages and the sensors are brand new.

I have two gages off the same type. One for each bank. And thay have the same issue.

Except that that I haven't been able to verify with a another wideband.

I would look for exhaust and intake leaks to start. Then verify maintenance. Perhaps the MAF sensor or stock o2 sensors are 10 years old and not working properly.

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