1991 Oxygen sensor connector different CODE 41 | Ford Explorer Forums - Serious Explorations

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1991 Oxygen sensor connector different CODE 41


Active Member
October 25, 1999
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I replaced my oxygen sensor today in my 1991 Explorer. The connector was slightly different. By cutting off one of the tabs, it fit fine. (Advise of the parts person.)

Well go figure, now I have a code 41. (No code previously.)

I had the parts man look at 1988 - 1990 Bronco II and 1991 - 1993 Explorers and it was the same part number.

What gives? Anyone else have this problem?

Thank you, Doug

what is a code 41?

Code 41 is
41 (R) System lean - Fuel control
(M) System was lean for 15 seconds or more (no HO2S switching) - Fuel control

As to why it would show lean? I don't know.. I'm assuming you reset the computer after chaing the o2 sensor? Normally the computer uses what it sees from the o2 to figure out how much fuel to put in... sooo if the o2 sensor is reading correctly the computer will adjust the fuel mixture to keep it optimum...


Correct me if I'm wrong, but a lean reading from the O2 sensor means the computer is seeing a low voltage; always. Could be caused by (amongst other things) a broken wire/bad connection between the sensor and the computer.