Honda Car Forum

I had some lean stalling on the interstate then the computer threw a
code, and everything was fine after that for few hundred miles. The
code is 41 and 43. 41 is listed as O2 sensor and 43 as lean mix. Is
the lean mix the cause or the effect of the O2 sensor code?

On Feb 1, 6:58 pm, "runde...@mail.win.org" <runde...@mail.win.org>
wrote:
> I had some lean stalling on the interstate then the computer threw a
> code, and everything was fine after that for few hundred miles. The
> code is 41 and 43. 41 is listed as O2 sensor and 43 as lean mix. Is
> the lean mix the cause or the effect of the O2 sensor code?

So I'm still stuck with the code 41, after replacing the O2 sensor and
recetting the ECM.

I measured 13.39V across the heater at the open end harness, and a 10
ohm resistance of the O2 sensor. The replacement is a Bosch...

This is an EX where the O2 sensor is in the exhaust pipe.

I'm stumped.

julia.albath@gmail.com wrote:

> So I'm still stuck with the code 41, after replacing the O2 sensor and
> recetting the ECM.
>
> I measured 13.39V across the heater at the open end harness, and a 10
> ohm resistance of the O2 sensor. The replacement is a Bosch...
>
> This is an EX where the O2 sensor is in the exhaust pipe.
>
> I'm stumped.

Get that Bosch sensor out of there and put an OEM sensor in its place.

High Tech Misfit wrote:
> julia.albath@gmail.com wrote:
>
>> So I'm still stuck with the code 41, after replacing the O2 sensor and
>> recetting the ECM.
>>
>> I measured 13.39V across the heater at the open end harness, and a 10
>> ohm resistance of the O2 sensor. The replacement is a Bosch...
>>
>> This is an EX where the O2 sensor is in the exhaust pipe.
>>
>> I'm stumped.
>
> Get that Bosch sensor out of there and put an OEM sensor in its place.

-----------------------------

If you search this NG, I recall more than one person who tried multiple
sensors from bosch, then put in a good OEM and solved the problem.

'Curly'

On Mar 18, 12:25 am, motsco_ <mots...@interbaun.com> wrote:
> High Tech Misfit wrote:
> > julia.alb...@gmail.com wrote:
>
> >> So I'm still stuck with the code 41, after replacing the O2 sensor and
> >> recetting the ECM.
>
> >> I measured 13.39V across the heater at the open end harness, and a 10
> >> ohm resistance of the O2 sensor. The replacement is a Bosch...
>
> >> This is an EX where the O2 sensor is in the exhaust pipe.
>
> >> I'm stumped.
>
> > Get that Bosch sensor out of there and put an OEM sensor in its place.
>
> -----------------------------
>
> If you search this NG, I recall more than one person who tried multiple
> sensors from bosch, then put in a good OEM and solved the problem.

For a code 41? The circuit seems fairly "dumb" so it's hard to
imagine what could be Bosched in it. The previous OEM sensor was
throwing a code 41 too..... the difference that I see is that the OEM
reads 16 ohms and the Bosch reads much less... but code 41
nonetheless. It's expensive to play part swapping with these things
because they don't take returns.

runderwo@mail.win.org wrote:
> On Mar 18, 12:25 am, motsco_ <mots...@interbaun.com> wrote:
>> High Tech Misfit wrote:
>>> julia.alb...@gmail.com wrote:
>>>> So I'm still stuck with the code 41, after replacing the O2 sensor and
>>>> recetting the ECM.
>>>> I measured 13.39V across the heater at the open end harness, and a 10
>>>> ohm resistance of the O2 sensor. The replacement is a Bosch...
>>>> This is an EX where the O2 sensor is in the exhaust pipe.
>>>> I'm stumped.
>>> Get that Bosch sensor out of there and put an OEM sensor in its place.
>> -----------------------------
>>
>> If you search this NG, I recall more than one person who tried multiple
>> sensors from bosch, then put in a good OEM and solved the problem.
>
> For a code 41? The circuit seems fairly "dumb" so it's hard to
> imagine what could be Bosched in it. The previous OEM sensor was
> throwing a code 41 too..... the difference that I see is that the OEM
> reads 16 ohms and the Bosch reads much less...

??? that won't make a difference? besides, this is a single wire
sensor - what are you testing with the ohm meter - it's not the heater
circuit because single wire sensors don't have one.

> but code 41
> nonetheless. It's expensive to play part swapping with these things
> because they don't take returns.

indeed. that's why people that have experience pay once for the oem
sensor, not multiple times for aftermarket. if price is the issue, go
to a junk yard - you can often pick up nearly-new oem sensors dirt cheap.

On Mar 19, 9:46 pm, jim beam <spamvor...@bad.example.net> wrote:
>
> ??? that won't make a difference? besides, this is a single wire
> sensor - what are you testing with the ohm meter - it's not the heater
> circuit because single wire sensors don't have one.

It's a four wire sensor. Heater, heater ground, signal, signal
ground. Supposedly isolated from the chassis too since it has a
separate signal ground, but that's probably worth a check next time
I'm under it.

> indeed. that's why people that have experience pay once for the oem
> sensor, not multiple times for aftermarket. if price is the issue, go
> to a junk yard - you can often pick up nearly-new oem sensors dirt cheap.

Why would a junkyard sensor be nearly-new? A good idea, anyway, I'll
grab me a few more to play with.

"runderwo@mail.win.org" <runderwo@mail.win.org> wrote in
news:1174404422.916894.259320@l77g2000hsb.googlegr oups.com:

> On Mar 19, 9:46 pm, jim beam <spamvor...@bad.example.net> wrote:
>>
>> ??? that won't make a difference? besides, this is a single wire
>> sensor - what are you testing with the ohm meter - it's not the
>> heater circuit because single wire sensors don't have one.
>
> It's a four wire sensor. Heater, heater ground, signal, signal
> ground. Supposedly isolated from the chassis too since it has a
> separate signal ground, but that's probably worth a check next time
> I'm under it.



You should not have a 4-wire sensor in that car. You should have a single-
wire sensor.

You've either got the wrong engine and/or ECU in there, or the wiring loom
has been hacked about to provide the grounds and feed for the heater on a
later-model sensor. Either way, it's might be wise to look elsewhere for
your ostensible sensor problem.

Have you considered that the sensor may have the wrong electrical
characteristics for the ECU it's married to?



--
Tegger

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

On Mar 20, 10:32 am, Tegger <teg...@tegger.c0m> wrote:
>
> > It's a four wire sensor. Heater, heater ground, signal, signal
> > ground. Supposedly isolated from the chassis too since it has a
> > separate signal ground, but that's probably worth a check next time
> > I'm under it.
>
> You should not have a 4-wire sensor in that car. You should have a single-
> wire sensor.

It has a 4 wire harness. Look it up on any parts site if you don't
believe me (this is an EX, it's not a sensor that goes into the
manifold, it goes into the top of the down pipe). It worked at one
point... then we fixed a burned valve, then after I saw the code 43
(which I haven't seen since, nor have I experienced the sputtering/
stalling that happened on that one road trip), the OEM sensor started
throwing a code 41... and now so does the new Bosch.

> You've either got the wrong engine and/or ECU in there, or the wiring loom
> has been hacked about to provide the grounds and feed for the heater on a
> later-model sensor. Either way, it's might be wise to look elsewhere for
> your ostensible sensor problem.

Yeah, but I don't know where to look. The only thing I could have
come up with is that the OEM sensor shorted to ground on the heater
and blew a fuse. But as far as I can tell from the wiring diagrams,
the fuel injectors are fed off the same supply, so if the fuse was
gone (tested it anyway, it's good) then the injectors would have no
supply. Then I made damn sure by checking voltage at the pig tail
with the ignition on, sure enough, there's battery voltage there. The
thing is, the code 43 and 41 showed up at the same time to begin
with. So it's possible that something went screwy with that circuit,
shutting off the injectors which threw the 43 lean downstream code at
the same time as interrupting the O2 heater circuit. But I can't
fathom what event would do that...

> Have you considered that the sensor may have the wrong electrical
> characteristics for the ECU it's married to?

Yes. That's what I am trying to figure out to get to the bottom of
this. What in the world is the ECM measuring to determine that it's
time to throw a code 41?

On Mar 20, 8:15 pm, "runde...@mail.win.org" <runde...@mail.win.org>
wrote:
>
> > Have you considered that the sensor may have the wrong electrical
> > characteristics for the ECU it's married to?
>
> Yes. That's what I am trying to figure out to get to the bottom of
> this. What in the world is the ECM measuring to determine that it's
> time to throw a code 41?

OK, so I thought about it a little more, since the heater circuit
ground goes through the ECM, then it is probably measuring the current
through the heater. So an internal leak to ground inside the sensor,
or incorrect impedance in the heater would affect the current that the
ECM sees. Can you think of anything else to check?