Writeup: O2 Sensor GMC '06 Envoy 5.3

CajunWon

Well-Known Member
#1
85k miles oem bank 2 sensor 1, O2 sensor. Intermittent p0059 p0055, both indicate issue with the heating within the sensor. The heater heats the sensor so it quickly goes into closed loop mode. Otherwise the sensor works fine after it warms.
Denso 234-4339
Loosen lug nuts, front right.
Lift frame so tire 6" off ground, brace with Jack stand.
Remove wheel.
Soak sensor Liquid Wrench cut with Naptha: 40 minutes.
Ride bike to AZ. Borrow O2 socket.
18" breaker bar for easy removal.
Easy part done!
Under hood: push air intake resonator to the left. Reach between tranny dip stick tube. Grab O2 wire to pull out sensor. Remove plastic anchor from bracket behind motor to give a few inches of wire slack and allow connector access. At connector, pull out gray lock pin to open snap and unplug.
Apply anti seize to new sensor, plug in, let it fall into place. Reach through wheel well to route it properly. Twist counter clockwise 4 turns, insert into exhaust pipe. Reinstall the plastic clamp, replace wheel, lower to ground. Done!

Found that sensor 1 of both banks, wire was rubbing on a heat shield. Had worn through protective sleeve. Used 2" of 3/8" plastic conduit with a drop of adhesive on both wires to solve issue.

I used TorquePro to graph sensor signals, which verified new sensor working.
 
Last edited:

northcreek

Well-Known Member
#2
Nice write up, I had to re-read the part where you rode your bike to AZ. ......I guess Arizona would be a bit of a ride..:duh:
 
#3
How did you get it plugged in again? On mine, it's up high to the side of the bellhousing with just room to get just one hand in there through the wheel well using a finger and thumb to get the two together. Took me over an hour just for that. My arm looked like I was in a fight with a feral cat.
 
OP
OP
CajunWon

CajunWon

Well-Known Member
#4
How did you get it plugged in again? On mine, it's up high to the side of the bellhousing with just room to get just one hand in there through the wheel well using a finger and thumb to get the two together. Took me over an hour just for that. My arm looked like I was in a fight with a feral cat.
There is the plastic clamp/anchor which holds O2 wire away from engine block. Pull out this anchor which provides enough slack in the wire to get both hands on the connector. Reinsert anchor when done.
 

BRomanJr

Well-Known Member
#10
I did that and there still wasn't enough slack. It you just have small hands compared to my meat hooks.
I did the same repair on my 5.3, and similar to how CajunWon described:
Without disconnecting sensor, unscrew it and pull sensor up the path the wire is run. Disconnect whole connector (barbed pin) from bracket and bring sensor and connector up near valve cover. At this point you can unplug sensor from connector and plug in new sensor into connector.

Lower sensor and wiring/connector back down the original path (I used a coat hanger to control the path). As CajunWon states. turn sensor backwards 4 turns and put back in exhaust, twist in by hand then torque. don't forget to clip the connector barb back into the original hole.

This works on both sides.
 
#11
Without disconnecting sensor, unscrew it and pull sensor up the path the wire is run. Disconnect whole connector (barbed pin) from bracket and bring sensor and connector up near valve cover.
:duh: That would work. That's the detail that was missing. Next time, I'll save myself the fight with the feral cat.

Added to FAQ.
 

Reprise

Gold Supporter
#12
Bookmarking this for the day when I have to replace my own. :goodpost: