Cadillac Owners Forum banner

1 - 3 of 3 Posts

·
Registered
Joined
·
1,622 Posts
Discussion Starter #1
I ran the codes today, i got 44 49 and 52. 52 is ECM memory rest, 49 is AIR system fault(i have no clue about that) and 44 is right O2 sensor lean. Also i ran a test on the O2 sensor and it needs to be replaced. But is the O2 sensor in the exaust manifold or the cat? and do i need to replace the right and left or is there just one sensor?

Also, what would cause the O2 sensor to run lean?
 

·
Registered
Joined
·
117 Posts
When an o2 sesor goes bad it does whatever it feels like.. In my case it made my car run rich by extending the injector pulse width and only putting out a connastnt .16 volts. It is supposed to put out .45 volts avg. It will oscillate when the car heats up and goes into closed loop mode. Oscillate meaning go up and down. you can go threw the car settings and see the changes its making in pulse width or what not.
 

·
Registered
94 Fleetwood Brougham
Joined
·
7,534 Posts
The sensor doesn't oscillate on its own, but fluxuates due to fuel mixture. Watch the O2 readings at WOT sometime, stable reading.

My guess is what is really happening is the PCM programming knows approx when the O2 SHOULD be up to temp, so while in warmup it "tests" the O2 and fluxuates the fuel mixture enough to start seeing it in the O2 sensor. Once it starts to read how it expects it, and all other conditions are met, it goes into Closed Loop.

Again, this is my guess on what happens.....

Tom
 
1 - 3 of 3 Posts
Top