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FAULT CODES 41,91,33

wickedstangs

Chula Vista, CA
Staff member
Administrator

After Replacing Everything above I decide to run the code scanner again. Because I will pass this time.:)

Ok I got codes:
KOEO 11 Test Good..

KOER 41, 91, 33
41 - HEGO(Ho2S) sensor voltage low/system lean
91 - HEGO(Ho2S) sensor voltage low/system lean
33 - EGR Valve not opening properly

I turned to some old sites, I used to lurk on when I was in the 5.0 days...
I went to www.sbftech.com and finally posted my first post there and been a member 2008 funny.

I was following one of there procedures for the 02 Sensor Codes that I got. and found it strange that the #19 HEGO Sensor Ground was located on the Throttle Body.
DSC_0268.JPG

I asked if its ok to be there and Joel5.0 very nice guy and help says
Joel5.0 said:
as long as a max resistance to ground of <5 ohms is maintained it will work fine. Check resistance at pin 49 in the EEC connector, EEC disconnected, to battery (-) terminal.

Well sure enough my resistance was way high showing an open.
SDC10089.JPG


Well, I placed the #19 ground in the right place now and both my faults 41,91 cleared.. I am a happy camper now..

Code 33 is the EGR Vacuum Regulator Valve (EVR) did a resistance check on it and sure enough it was bad..
DSC_0271.JPG


Replaced it and my codes 41,91,33 are gone. :)

I decided to run the code scanner one more time to make sure everything is good to go. And sure enough I get one more code:(

CODE 94
Just seems kinda odd since I had been getting codes 41 and 91, then I find my problem and fix it and then I'm getting Code 94 this is perfectly normal for more codes to show up after a lean code has been fixed.. The o2's can only really detect one problem at a time. And in the event that the 02's are reading lean or rich, those codes take priority over the themactor codes 94. So it can't detect the loss of thermactor air and a lean or rich code at the same time.
 
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