Annoying P0133 O2 Sensor (B1S1) Circuit Slow Response Code

M

mantiss

Test Drive
Location
Kennesaw, GA
I have an annoying O2 sensor code P0133 "O2 Sensor Circuit Slow Response Bank 1 Sensor 1" plaguing since Dec. 2022. At that time I was getting two codes (P0133 and P0031) and switched the sensor with the B2S1 to see if it was the sensor. Sure enough, the codes switched to Bank 2. Great! I bought a new O2 sensor, and voila! I passed the emissions test. A few months later, I started getting the P0133 code again (remember this was the good one from the B2 side). This time I noticed a leaking rocker (i.e., cylinder head) gasket because the O2 sensor wire was saturated with the leaking oil. So I replaced both LH and RH rocker covers/gaskets with new "Mitzone" red aluminum covers/gaskets. I inspected all the hoses and replaced the rock-hard PCV blowby hose. After installation tested (using DIY soapy water) all hoses and joints for leaks.

My mileage on a full tank shot up from a dismal ~276 miles to ~378 miles instantly. The Service engine light was finally clear and of course, after a week and a half, the pesky P0133 code came back. I upgraded my OBD II to the Launch CR529 tool and found two specific failures for B1S1 (see images attached for tests Id's 87 & 88). I wish the test details and meanings were better explained.

IMG_1767.jpgIMG_1768.jpg

So, I will be replacing the O2 sensor, but wanted to get any advice on what to check for, just in case something else is causing the upstream sensor(s) when attached to B1 to fail--twice.
 
Muadeeb

Muadeeb

Nissan al Gaib
Admin
Location
Dallas
Oil seepage could've damaged the sensor if it traveled down the wire into the unit itself. But your sensors are also (likely) 14 years old, so it was time.
 
M

mantiss

Test Drive
Location
Kennesaw, GA
Thanks for the quick follow-up. That was my thought as well, but I was wary of the lightning striking twice and the fact that there was no oil leakage (at least to the best of my knowledge/memory) on the first sensor. Just trying to be proactive. I will keep my fingers crossed.

P.S. I love the Procrastination quote btw. Story of my life and similar to one of my sayings, "Why do today what you can put off to tomorrow!"
 
M

mantiss

Test Drive
Location
Kennesaw, GA
Muadeeb said:
Oil seepage could've damaged the sensor if it traveled down the wire into the unit itself. But your sensors are also (likely) 14 years old, so it was time.
Click to expand...
You were right, the problem in this case was likely due to oil seepage from the cylinder head gasket that I had not detected until recently (the wires were saturated). I will be monitoring regularly (and maybe try to create some sort of shield to protect wires just in case) in the future.
 
You must log in or register to reply here.
Top