Car: 1996 Civic DX - Stock motor

Primary Oxygen Sensor - Heater circuit malfunction

Can someone explain to me what this CEL code is, im not really sure, i guess i have a bad o2 sensor?

Also i have a slightly cracked stock header in which a little bit of exhaust leaks out... I'm not sure but im guessing that might be a reason?

Someone please clear me up, thanks a lot.

 

ya your o2 heater went out.. you need a new o2 sensor

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDMlyfestyle &raquo;</TD></TR><TR><TD CLASS="quote">ya your o2 heater went out.. you need a new o2 sensor</TD></TR></TABLE>

 

bringing it back from the dead, kinda

Is it definently the O2 sensor. I don't have my heater/coolant lines hook up. Could this affect it?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BeavisB16 &raquo;</TD></TR><TR><TD CLASS="quote">I don't have my heater/coolant lines hook up. Could this affect it?</TD></TR></TABLE>

No.

You need a multimeter to troubleshoot the problem. Disconnect the O2 from the main engine harness and measure the resistance between the two black wires. It should be between 15-40 ohms - may even dip down to 13 ohms which is acceptable as well.

If you don't have a meter, then just replace it and see where that gets you. An expensive guess if you're wrong though....

 

I just converted to OBD-1 and this is my only code now. The O2 sensor worked fine before but I dont know how old it is.

 

Did you have to convert from a 1-wire to 4-wire O2?

What ECU are you using now?

 

what the O2 heater circuit does is moniter the current and voltage drop across the heater circuit.

So if it doesnt see a voltage drop and a certain current flow it throws the code. 90% of the time its the heater circuit inside the O2 sensor 10% is the wiring.

 

yeah I converted from 1 wire to 4 wire O2 sensor. I am using the p28 for the time being. The O2 sensor was wokring completely right before the swap into the CRX, i just don't want to fork out the $150 if it isn't the O2 sensor.

ok, thanks for the info about the heater circuit

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BeavisB16 &raquo;</TD></TR><TR><TD CLASS="quote">yeah I converted from 1 wire to 4 wire O2 sensor.</TD></TR></TABLE>

Sounds like this might be the problem then. If you're reasonably sure the O2 sensor was fine before using it in this conversion, then you need a multi-meter in order to troubleshoot.

What is the resistance of the O2 heater element?

Is +12v getting to the heater with the key 'on'?

Do you have continuity from all wires to their respective locations at the ECU?

Are any wires shorted or open?

All these Q's can be answered with the help of a meter.