" > wrote in
ups.com:

> On Mar 20, 8:15 pm, " >
> 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.



OBD-II ECMs do measure current from the heater wire. That's how it knows if
the heater's malfunctioning. However, I don't know if pre-OBD-II ECUs
monitored the heater wire or simply provided ground.

I had a better look at the manuals I've got, and it appears my original
conclusion was wrong: Your car DID originally come with a 4-wire sensor.



> 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?
>


Corrosion at the connector, high wire resistance, I don't know what all
else.

If you post your question to the group rec.autos.tech, there is at least
one extremely knowledgeable and experienced technician (Comboverfish) who
posts there. He would be the best one to answer this one, as he has large
amounts of Honda experience.


--
Tegger

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