90 BII 2.9, OBD1 shows code 41 as "HEGO HO2S", is this the regular O2 Sensor?

BillRod · 05-10-2012, 02:44 PM

Hi All

Daughters 90 Bronco II has been idling a bit funny. every now and then it the rpms will dip a little. Can't really tell except she has a bit louder than quiet exhaust so you can hear it more than feel it.

I put my OBD1 reader on it and it had a stored code and hard code 41.
The OBD1 book states code 41 as:

There is one KOER code 41:
"HEGO (HO2S) Sensor voltage low / system lean".

There are two KOEO Stored code 41's:
First one is "HEGO (HO2S) Sensor signal out of range / always lean".
Second one is "No HO2S Switching Detected".

Is the HO2S the regular O2 senor in the exhaust line?
Never heard of it referred to as and HO2S before.

Any thoughts or info would be much appreciated.

Thanks
Bill

Psychopete · 05-10-2012, 03:05 PM

Yes. 41 is the oxygen sensor sensing too much oxygen in the exhaust, most of the time, versus a bad sensor. Could be oxygen sensor ground also. If there's an exhaust leak before the o2 sensor, I could see you possibly getting this code. Since it's thinking it's running lean, it is adding more fuel, probably explains why your idle isn't consistent at times.

BillRod · 05-10-2012, 03:13 PM

So it's probably not a bad sensor since I can hear a small exhaust leak upstream. I guess I will start looking for the leak.

Thanks
Bill

Psychopete · 05-10-2012, 03:24 PM

IME 41 is almost always the oxygen sensor doing the right thing; telling you it's sensing too much oxygen. Mis fire, vacuum leak, all sort of stuff can cause that code.

**AllanD** · 05-11-2012, 12:46 PM

"HEGO" = Heated Exhaust Gas Oxygen (sensor)

There is actually a heating element inside the sensor to bring it up to operating temperature.

AD

BillRod · 05-12-2012, 12:46 PM

Found a couple small vac leaks and corrected them. error is gone.

Thanks
Bill

05-10-2012, 02:44 PM	#1
BillRod Member Join Date: Dec 2008 Location: Colorado Springs CO Year: 2/88's, 1/94 Make: Ford Model: 88 & 94 Rangers, 88 BroncoII Engine: 94=4.0, Both 88's=2.9 Class: All are 4x4 Posts: 139 Rep Power: 9 iTrader: (0)	90 BII 2.9, OBD1 shows code 41 as "HEGO HO2S", is this the regular O2 Sensor? Hi All Daughters 90 Bronco II has been idling a bit funny. every now and then it the rpms will dip a little. Can't really tell except she has a bit louder than quiet exhaust so you can hear it more than feel it. I put my OBD1 reader on it and it had a stored code and hard code 41. The OBD1 book states code 41 as: There is one KOER code 41: "HEGO (HO2S) Sensor voltage low / system lean". There are two KOEO Stored code 41's: First one is "HEGO (HO2S) Sensor signal out of range / always lean". Second one is "No HO2S Switching Detected". Is the HO2S the regular O2 senor in the exhaust line? Never heard of it referred to as and HO2S before. Any thoughts or info would be much appreciated. Thanks Bill __________________ We're an all Ford family... 95 F150 4x4 Ex cab Big Six 5spd (Mine). 94 Ranger 4x4 Ex cab 4.0L 5spd (Wife's). 00 Explorer 4x4 4.0L Auto (Son's). 90 Bronco II 4x4 2.9L Auto (Daughter's). 93 Ranger 4x4 Ex cab 4.0L 5spd (Son's). 97 Taurus (Spare).
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05-10-2012, 03:05 PM	#2
Psychopete Member Join Date: Aug 2007 Location: Fort Wayne, Indiana Year: 1987 Make: Ford Model: Ranger Engine: NONE Class: 2WD Used For: Working on Posts: 3,203 Rep Power: 21 iTrader: (5)	Yes. 41 is the oxygen sensor sensing too much oxygen in the exhaust, most of the time, versus a bad sensor. Could be oxygen sensor ground also. If there's an exhaust leak before the o2 sensor, I could see you possibly getting this code. Since it's thinking it's running lean, it is adding more fuel, probably explains why your idle isn't consistent at times. Last edited by Psychopete; 05-10-2012 at 03:08 PM.
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05-10-2012, 03:13 PM	#3
BillRod Member Join Date: Dec 2008 Location: Colorado Springs CO Year: 2/88's, 1/94 Make: Ford Model: 88 & 94 Rangers, 88 BroncoII Engine: 94=4.0, Both 88's=2.9 Class: All are 4x4 Posts: 139 Rep Power: 9 iTrader: (0)	So it's probably not a bad sensor since I can hear a small exhaust leak upstream. I guess I will start looking for the leak. Thanks Bill __________________ We're an all Ford family... 95 F150 4x4 Ex cab Big Six 5spd (Mine). 94 Ranger 4x4 Ex cab 4.0L 5spd (Wife's). 00 Explorer 4x4 4.0L Auto (Son's). 90 Bronco II 4x4 2.9L Auto (Daughter's). 93 Ranger 4x4 Ex cab 4.0L 5spd (Son's). 97 Taurus (Spare).
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05-10-2012, 03:24 PM	#4
Psychopete Member Join Date: Aug 2007 Location: Fort Wayne, Indiana Year: 1987 Make: Ford Model: Ranger Engine: NONE Class: 2WD Used For: Working on Posts: 3,203 Rep Power: 21 iTrader: (5)	IME 41 is almost always the oxygen sensor doing the right thing; telling you it's sensing too much oxygen. Mis fire, vacuum leak, all sort of stuff can cause that code.
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05-11-2012, 12:46 PM	#5
AllanD RBV Technical Advisor Join Date: Jun 2001 Location: East-Central Pennsylvania Year: 1987... sorta Make: Ford Model: Ranger Supercab Engine: '93 4.0 Class: 4x4 Used For: Roadtrip Warrior Posts: 7,169 Rep Power: 47 iTrader: (18)	"HEGO" = Heated Exhaust Gas Oxygen (sensor) There is actually a heating element inside the sensor to bring it up to operating temperature. AD __________________ Gun Control - A theory espoused by some monumentally stupid people; who claim to believe, against all logic and common sense, that a violent predator who ignores the laws prohibiting them from robbing, raping, kidnapping, torturing and killing their fellow human beings will obey a law telling them that they cannot own a gun.
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05-12-2012, 12:46 PM	#6
BillRod Member Join Date: Dec 2008 Location: Colorado Springs CO Year: 2/88's, 1/94 Make: Ford Model: 88 & 94 Rangers, 88 BroncoII Engine: 94=4.0, Both 88's=2.9 Class: All are 4x4 Posts: 139 Rep Power: 9 iTrader: (0)	Found a couple small vac leaks and corrected them. error is gone. Thanks Bill __________________ We're an all Ford family... 95 F150 4x4 Ex cab Big Six 5spd (Mine). 94 Ranger 4x4 Ex cab 4.0L 5spd (Wife's). 00 Explorer 4x4 4.0L Auto (Son's). 90 Bronco II 4x4 2.9L Auto (Daughter's). 93 Ranger 4x4 Ex cab 4.0L 5spd (Son's). 97 Taurus (Spare).
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