Did you already replace the upstream oxygen sensor, or did you measure the resistance accross the oxygen sensor heater? Thanks,
It's very common for the o2 sensor's heater to fail and cause this code. On the sensor, depending on what brand it may be, there will be two identical colored wires of the four. There may be (2) white, (2) black, etc. These are your heater wires. Commonly, if you place the meter in ohms, and measure across them while the sensor is disconnected, it will show an open circuit (no reading). This will confirm the oxygen sensor repalcement. Now, if there is another reading, let me know what it is and i'll look up the specification.
Perfect!, this means bad oxygen sensor. Now, be carefull of the one you purchase. The dealer is the best source but will cost you an arm and a leg. If you purchase aftermarket, or on the internet you may get a bad one, which may cause all sorts of new problems. So, whichever you decide to use, measure the new sensors resistance first, than if your engine runs different after installation, it will entail a defective unit. These sensors are very fragile and at the dealer thy're protected from damage, whereas in the aftermarket they're dropped on the floor, packaged incorrectly, etc. Let me know if you need help after you get the new one in. Also, it's easier and smarter to change the sensor on a cold engine, and make sure you keep the wires away from the exhaust manifold.
Sorry, I got your second question a little late. Now, there are a couple of different methods Honda uses to power the heater. You should either have voltage on the engine side connector on the related wires, or connect your meter negative to ground and than probe each terminal with the Ignition on, you should read voltage.
What about accross the terminals which the black wires would connect? It's rare to have both an open oxygen sensor and a fault in the wires or computer...let me know, thanks.
Awesome...good job, it happens. That's what makes you a good technician, to double check your work. I think you'll be just fine after the replacement, and the best part is you saved a bundle on diagnostics.
No problem, and thanks for the bonus, it's very generous.