From the battery positive to heater pin on o2 connector? Sorry I'm just double checking don't want to blow anything up ?
No no don't do that
From the battery positive to heater pin on o2 connector? Sorry I'm just double checking don't want to blow anything up ?
Hi Bernie. I'm feeling a little nervous about this post because you obviously know more about the electronics than I do. However because, with my daughter in law owning a Jazz - and thinking of replacing it with a much newer one - and my interest in the 1.8 i Vtec Civic, I've been looking into air/fuel ratio sensors (also, I believe, called "wide band" O2 sensors) which are used by a lot of these far eastern manufactures. I'm only just starting to get my head round them.λ (O2) sensor's heater is two wires fed and the signal is returned to ECU with two wires, so it should not be sensitive to battery to boddy earthing, while A LOT of other errors and misbehavior would pop-up.
Here are some info about the λ sensors ...
BRs, Bernie
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@ Jackwhoo: the λ heater is ground controlled by the ECU, positive is (should be) therefore ALWAYS present ! So the diagnostic method you gave is wrong ...
Hello Bernie,
Take it easy with your criticism.
I disagree that what I have suggested is wrong;
Yes the ecu grounds a heater wire from o2 sensor to turn it on .
Yes the positive feed to the o2 sensor heater should be there when relay turns it on...........but ........
What if .........
The fuse to o2 sensor heater has blown?
The o2 sensor wiring is damaged somewhere ?
The above two cases will cause o2 sensor heater code.
Trying to help the original poster with an easy test to start with.
Jack
Hello Jack,
sorry if you my reply as a critic, it was certainly not my intention !!
But the thing is that proving positive is present won't tell anything about the command circuit ... Sure enough, one have to check the fuse(s) and relay (if involved), this is absolute basic checks, isn't it ?
We (at least me) expect a minimum of knowledge from the forumers who post technical questions, the others would probably go directly to the nearest service or call AAA, so we (I) believe the basics has already been done ...
Finally, in order for the heater to heat, we need BOTH positive and negative present at the connector AND the heater itself being not cut/grounded: the very first and only valuable test is to check if those conditions are met.
- check the fuse and the relay (should click at contact on)
- check 12v is present at the λ sensor connector
From there, if everything is ok, one should proceed further by checking for signal wires continuity, connectors etc.
BRs, Bernie
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