Car boggs and been driving like this for 1 year so far. How do I go upon checking my voltage? I get CEL and it bogs like ****. Like no power at all. Still get around 350 miles to a tank which can hold 10 gallons. I read what the helms manual said but I dont get any readings when I use my multimeter on the ends of the O2 sensor. Any help please? Thanks in advance. I know I'm a noob at this.

 

your still doing good, my vx has a bad O2 and im only getting about 27 MPG. i need to know how to check it also. bump for us.

 

All I really need to know is how do I check the voltages on an O2 sensor if it is unplugged? Doesn't that meant that it isn't getting any power so no voltages would show up on my multimeter. Not sure what the helms manual is talking about. Need help badly please!

 

which CEL? O2 sensor? replace it.

The VX O2 is not easy to check. If the ECU says it's bad and you havn't done lots of wiring changes to the engine harness, it's bad.

 

There's no easy way to check the voltages except with the test harness that plugs into the ECU that the Helms talks about. 99.9% of the time it's not going to be the wiring (unless you've been messing with it like Relic1 said), it's the sensor, esp if you've got more than a few miles on it.

I've had the CEL for bad O2 for years, and my mileage decreased (gradually) from low-40's to low-to-mid 30's. Didn't get any bogging, though. Changed it and it's only been a few tanks but mileage has been back up to 40.