Found this thread on the US Impreza forum - O2 sensor - Is that the same part as the over-sensitive and fragile MAF on European MY99-00 cars?

Anyone with an input to this one?

-- Is there something wrong/silly about my question??? --
Thought it would be nice to know whether it's the MAFs the US Subaru dealers are recalling, in case my own MY00 MAF should suddenly start causing trouble. (I do have a KN panel replacement filter installed, which as far as I have understood, could increase the risk of a MAF failure.)

[This message has been edited by SSE (edited 24 March 2001).]

SSE
The answer is NO! The O2 sensor is the lambda sensor in the exhaust just after the turbo. It senses the amount of oxygen in the exhaust, too much-lean too little-rich. The management system can then adjust injector opening time to compensate. they have been known to go U/S.
JohnD

If the Lambda sensor is buggered then the ECU should notice crap readings comming from it and will then light up the Check Engine light.

At this point, take it to the dealer and they will work out this is the problem and change it for you.....

Matt.