AEM wideband o2 sensor doesn't work when cold outside?

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Dec 14, 2004 | 12:32 PM

Chris F

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From: Chicagoland, IL

AEM wideband o2 sensor doesn't work when cold outside?

Hey guys,

Any of you have the AEM WBO2 in a colder area?

When it's cold out here (20F?), the AEM flashes "111." repeatedly for a minute, and then starts working.

Normally it flashes "111." "222." "333." .... "999." "AEM" "P01" <--- something like that, and then starts reading.

I guess it's failing its power-on self test and in a rolling reset?

Anyone else see this? Should I be worried/looking for a new one under warranty? It's 6 months old, haven't had a problem until three evenings this winter it's been cold.

Once it starts working, its fine, so I might just live with it until it really dies.

Dec 14, 2004 | 01:07 PM

dc2legend

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From: Cleveland, Oh

Re: AEM wideband o2 sensor doesn't work when cold outside? (Chris F)

Sounds like it needs to warm up, I don't know but i'm assuming the AEM o2's aren't heated?

Dec 14, 2004 | 02:03 PM

Chris F

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From: Chicagoland, IL

Re: AEM wideband o2 sensor doesn't work when cold outside? (dc2legend)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dc2legend »</TD></TR><TR><TD CLASS="quote">Sounds like it needs to warm up, I don't know but i'm assuming the AEM o2's aren't heated?</TD></TR></TABLE>

AFAIK not heated. But the gauge always at least reads SOMETHING even if the car isn't running (14.7:1 i think is it's cold reading). It's not the sensor I don't think, just the gauge. The sensor should be pretty damn hot after just a few seconds of idle, but it takes a full MINUTE (or two) until the gauge wakes up.

-Chris

Dec 14, 2004 | 02:10 PM

notoriousB

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From: North of Boston, MA, USA

Re: AEM wideband o2 sensor doesn't work when cold outside? (Chris F)

all wbo2's are heated. heated very precicely actually. there is a warm up time, and until it's at operating temperature you will not get accurate readings.

Dec 14, 2004 | 04:10 PM

Chris F

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From: Chicagoland, IL

Re: AEM wideband o2 sensor doesn't work when cold outside? (notoriousB)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by notoriousB »</TD></TR><TR><TD CLASS="quote">all wbo2's are heated. heated very precicely actually. there is a warm up time, and until it's at operating temperature you will not get accurate readings.</TD></TR></TABLE>

Cool.

(I doubt "very precisely" since EGT's are all over the place, you couldn't keep it at any exact temperature with any precision.)

I guess no one else's AEM WBO2 Gauge freezes up when its cold?

Dec 14, 2004 | 05:24 PM

BigMoose

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From: Milky Way

Re: AEM wideband o2 sensor doesn't work when cold outside? (Chris F)

Just for folks information. Yes, wideband O2 sensors must be kept at an accurate temperature. This is done with a PID feedback loop to the heater, typically regulating heater PWM period in order to hold the sense nerst cell at its specified operating resistance. The resistance of the nerst cell is directly related to cell temperature.