OK, I posted about the O2 sensors yesterday, because I bought 2 new ones...and someone replied that they actually have 4 O2 sensors (California). Well, turns out so do I. So now I am reconsidering the whole job.

Here's the question:

Is there any way to tell which sensor is setting off the "Check engine" light, or do you have to replace all 4.

damn california!

It was a suprise for me to find 4 sensors on my non calif. 4.0.
Besides the $300 for the 4 o2's the job really was not bad.
Just remember like I said b4 i had to cut wires from the 1 sensor the socket would not fit.
I'd like to know how many states is the Calif. engine required in.
Does it make a difference or does D/C install what ever engine into NON Calif. delivered trucks?
Asked at the dealer and they had no clue.

I'd like to know how many states is the Calif. engine required in.
Does it make a difference or does D/C install what ever engine into NON Calif. delivered trucks?

It does make difference
It the past, non California cars were referred to as federal vehicles or "49 staters".
No more.
Seven North eastern states, New York, New Jersey, Massachusetts and 4 others now use California's auto emission standards.

Quote:
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"damn california!"
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Its a good thing for California - if it were not for strict CA emissions regulations, we would be choking to death here.

Bob D.
The truck was built for sale in NY.
I even contacted a NY dealer (web sales) with the VIN and he wasn't (wouldn't) able to tell me how many O2s were in the truck. He said he had to contact D/C for part numbers. Never heard from him again. I guess he didn't need the $350 sale.

Its a good thing for California - if it were not for strict CA emissions regulations, we would be choking to death here.

I know...Just making for a difficult job here

a97ducati748 - have u checked the codes, it will tell you the code which will tell you which O2 Sensor is illuminating the CHECK ENGINE light.

most likely it is one of the 2 Pre-Cat sensors, which would tell you the engine is running rich/lean. The 2 post-cat. tell the operation of the Catalytic converter, if it is filtering properly, etc.....

the code should tell you upstream sensor or downstream sensor.