O2 question

[SHERMAN FJ62]

My truck is saying driver side upstream 02 sensor is bad. Do I need to replace the upstream and down street at the same time or OK to do just the one?

Any tips on removing and replace them? Looks like screw in and out?

Thanks

Dealer

Wanted $300 to do repair, no thanks

 

[kbahus]

What are the actual codes?

 

[langsen]

You should be ok just doing the one upstream sensor. But people recommend to replace them in pairs (both upstream sensors at once) assuming that if one has gone bad the other is on its last legs as well. The sensors are under $50 each online and AutoZone rents the O2 sensor wrench for free, so it isn't too bad price wise. The hardest part for me was unclipping the wiring connector. Took probably 15 minutes per side, no need to jack it up off the ground.

 

[pnolanIH8MUD]

I was getting a P0135 message on my ScanGuage II. It was the upstream sensor on the driver side. To access, I used my ramps to get comfortable access then removed 6 12mm bolts to remove the poly underbelly shield.

Once that was removed I located the sensor just above the manifold mount. This O2 sensor is the non-flange style so the 22mm or 7/8 O2 Sensor wrench with a 3/8 wrency fit easily over the connecting wires. As a Texas truck, I didn't have rust and the sensor popped loose rather unceremoniously. I was able to turn it the rest of the way wearing gloves. The connector was easily disconnected by pressing down on the lever on the higher side of the plug. Take a look at your replacement to see which side the release is on. I took my time and it took me about 20 minutes to replace the one side. I reinstalled the underbelly shield. I supported the underside of the truck on the frame with a sizable jackstand just in case of ramp failure. The up side is that once you have the shied off, you can see and easily access the lower/downstream flange style O2 sensor. I've attached a photo to help orient the next mechanic. Upon completion, I reattached the ScanGuage II and cleared the CEL. Done.

Forgot to add. Bought the Denso O2 sensor on Amazon for $45. Purchased Antiseize $4. Wrench from Harbor Freight $7. For reference, I called Champion Toyota Parts in Austin who quoted me $250 for just the O2 sensor itself. Labor was extra. So, fixed myself for under $75. Makes the prospect for changing out the others a no brainer but not currently necessary.