Hi all, Just got this one back, it has been away now over a week and no codes. We now have a genuine Ford O2 sensor which across the heater circuit measures 6.4Ohms the NGK it is replacing is 6.2Ohms negligible difference on a 200K scale. I’m trying to attach the scope trace to this post, the blue line is battery feed and the red is the earth control to the ECU. All that varies is the earth return with revs I have taken one at 4000rpm & one at idle. May be someone could interpret these images and throw some light on the matter. The images are from the new genuine sensor; unfortunately one of the techs grabbed the job before I was aware and changed the sensors before I could scope the old NGK unit. Just hoping the genuine O2 sensor does the job as it is the first NGK that we have yet had problems with.
John Kennard

Just got the chance to re-edit this and add in the NGK Scope patterns which I went back & fitted, just in case there was a difference. To start with the genuine Ford sensor was a NGK, identical to the factor NGK sensor, except it had Ford & Ford part No. stamped into the metal sleeve. A Ford tech told me NGK's are standard on Fords. The lower links are the NGK Patterns. I will revisit this link in 2 weeks time if the light has stayed out.
John Kennard.

http://i1090.photobucket.com/albums/i364/cedargarage/Y697RCBFocusO2HeaterIdle1.jpg Genuine @ Idle

http://i1090.photobucket.com/albums/i364/cedargarage/Y697RCBFocusO2Heater4000rpm1.jpg Genuine @ 4000 Rpm

http://i1090.photobucket.com/albums/i364/cedargarage/Y697RCBFocusIdleNGK.jpg NGK @ Idle

http://i1090.photobucket.com/albums/i364/cedargarage/Y697RCBFocus4000RpmNGK.jpg NGK @ 4000 Rpm