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Car has check engine light coming on that shows a downstream O2 sensor, been lazy and driving car for months clearing code.
Time for oil change so while it's on ramps I'll replace it, was looking at Bosch but while searching google saw some fail quick and to use AC Delco, but also said Denso is the one to use now.
By the way, would a downstream O2 sensor change fuel economy or the way car runs?
1999 6 speed convertible, still stock. 89000 miles
What was the code number? It would indicate which sensor was having the problem and what said problem was. As far as sensor brands, I believe that Denso makes the OE sensors for GM.
Quality pieces. As far as fuel economy or engine performance, rear sensors have no effect. They only function to report on the state of the cat. Fuel control from rear sensors only became a thing in 2010 or 2011.
Bank 2 sensor 2 heater circuit. Most likely cause is a burnt heater element inside the sensor. The main reason that I asked is to rule out sensor performance problems. If you have a DVOM you can ohm out the senor heaters to compare side to side. Or just replace them.
Yes you can ohm the heater on the drivers side and compare the reading to that of the passenger side. All things being equal, The sensors have been through the same amount of heat cycles, and one of them has had a heater failure. Chances are that the other one will soon follow. They don't have to be done in pairs though.
Compare the ohms on the passenger with the driver's side downstream 02 sensors?
By the way I was just planning on replacing the one that is setting the code, are they supposed to be replaced in pairs?
Denso makes the OEM sensors, so if you get an AC Delco part, it'll be a Denso in the box. All four of mine have been replaced with Bosch and it's been ok for several months now. I think the Densos were cheaper, so I'd probably just recommend that.
No need to replace them in pairs.
Also, it's at least worth checking the fuses for the heater circuit if you haven't already.
Yes the sensors are four wire, Don't have a diagram in front of me but if memory serves, pink to black is the heater circuit on the car side of the harness. The sensor may come with two white and two black wires. Find a wiring diagram to verify. Also check for power on the heater feed, could be a blown fuse.
I used Denso and they work fine. Got them from Rock Auto for a good price.
First I installed some El Cheapo O2 sensors they didn't work. Don't try that!
As others stated, downstream sensors do not affect performance or fuel economy.
You might consider replacing all four while you are under there and have the tools in hand.
They are fairly easy to replace. Soak them good with WD40 before removing old ones.
Get this loaner tool from AZ. Will probable need a cheater pipe to break them loose.
Doing all 4 would be cool, but I have other issues to fix on car, A/C compressor is out and Phoenix area is awful hot!
Also I was planning on buying and attempting to install a Katech remote bleeder for my clutch. (On the reviews someone was able to get it on with drivetrain in place)
Also have noticed what may me a manual transmission oil leak.
I used Denso and they work fine. Got them from Rock Auto for a good price.
First I installed some El Cheapo O2 sensors they didn't work. Don't try that!
At first I was looking at the cheap ones at Rock Auto, but figured you get what you pay for.
07-08-2018, 02:51 PM
What brand oxygen sensor?
