[maverickdave]

Ive got a 2004 Colorado 3.5l 4x4 z85 LS

Have 3 codes.
PO030 heated oxygen sensor heater control circut bank 1 sensor 1.
PO134 Heated oxygn sensor no activity detected bank 1 sensor 1
PO135 Heated oxygen sensor malfunction bank 1 sensor 1

two questions. which sensor is bank 1 sensor 1? And would just changing the sensor fix the issue?? or do i have something else going on with the heater circut??

thanks for any input :salute:

 

[cdk]

sensor 1 should be the one in the exhaust manifold, and #2 would be under the truck by the 2nd cat.
how many miles on the truck? may be time to change the sensor out? i'm not sure

 

[maverickdave]

110k

 

[maverickdave]

is that the one right on top on passenger side of motor

 

[cdk]

yea, it should be in the exhaust manifold coming thru the heat shield.

 

[maverickdave]

thanks appreciate the info and input. one last question lol is that the downstream or upstream

 

[2fingermagic]

thanks appreciate the info and input. one last question lol is that the downstream or upstream

Upstream is by the manifold... Downstream is by the 2nd cat... Easy way to remember is exhaust exit is downstream from engine... Upstream is engine bay


Sent from AutoGuide.com Free App

 

[Rick_crew]

FWIW...

In the opinion of my favorite mechanic, O2 sensors are good for about 60K miles.
They may continue to operate long past that, but after 60K-ish they need to be replaced for best operation.

My truck ran OK at 110K or so, but not with the best driveablity, and the idle was rough.
Changing the upstream O2 sensor made a huge improvement.
When I learned how much better it drove and idled I was kicking myself for not doing it sooner.

Don't know what the factory recomends, but I don't care.
They're cheap and easy to change, so..

 

[2fingermagic]

Agree with Rick... I have 18x,xxx miles on my 06 crew cab and I just replaced my sensors. They were original and it took me all of a half hour to switch out both. With the exception of the upstream sensor being a PITA.


Sent from AutoGuide.com Free App

 

[Rick_crew]

... And would just changing the sensor fix the issue?? or do i have something else going on with the heater circut?? ..

The heater is built-in to the sensor.
I think you can disregard that part, those codes are just telling you that the signal from the o2 sensor is out-of-spec.

The reference to "heated" in the code is just the text that someone threw in because its how he was accustomed to refering to the o2 sensors in conversation. The code is telling you that the sensor is bad (or else there's a wiring problem to the sensor if that be the case).