Wideband 02 - Heater Voltage

SWEliseK20A · Post by **SWEliseK20A** » Thu Oct 01, 2009 4:15 am

As per a previous post,

Can someone tell me what voltage I should see on the wires for the lambda sensor heater. i see close to battery voltage on initial start-up for round about 30 seconds, then it slowly drops, down through 9, 8 etc and eventually just fluctuates between 2.5 to 5 volts. Does the heater always get some sort of voltage or when it shuts off should I see 0v?

It is a PRB ECU into a UK Type R (K20A2) and the wiring for the 02 sensor is Exaclty as shown on the Hondata website.

Thanks in advance,

Scott

Post by **Spunkster** » Thu Oct 01, 2009 11:02 am

Is it reading correctly?

SWEliseK20A · Post by **SWEliseK20A** » Fri Oct 02, 2009 12:40 am

Yes it is reading correctly but I dont want the heater staying on permanently and burning it out, thus requiring a new sensor every month or so. I'm aware the the heater is only meant to be on initially and then shut off, my question is, should it then see 0v or does it always see a minor voltage, ie the 2.5 to 5v that I am seeing when I meter the heater pins on the sensor?

cranny · Post by **cranny** » Fri Oct 02, 2009 6:48 am

im pretty sure the heater comes and goes as its running as well and needed to keep a certain temp isnt it? maybe im wrong.

Post by **Hondata** » Fri Oct 02, 2009 7:24 am

The heater is duty cycle controlled depending on the requirements necessary to keep the o2 at the correct temperature. Pretty much they run the whole time. Also, remember that the ECU controlls the current return side of the heater, so you'll see 12V on the HTC+ side always, and 0V on the HTC- side when the heater is on.

SWEliseK20A · Post by **SWEliseK20A** » Fri Oct 02, 2009 9:00 am

many thanks for the replies