Focus Fanatics Forum banner

1 - 3 of 3 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter #1
I've been measuring upstream o2 sensor voltages trying to diagnose a P0420 code on my 2012 SEL MT. I noticed it stays steady at 1V most of the time, but on deceleration engine braking, the voltage jumps to 2.0V for a bit and then will come back towards 1V. Is this normal?
 

·
Registered
Joined
·
6 Posts
Discussion Starter #3
I understood it to be the relation of switching between the upstream and downsteam, so I'm considering the behavior of both. The downstream stays consistent at idle, bit starts to vary a bit with throttle on/off. I don't think it's unusual, but I'm not sure.
 
1 - 3 of 3 Posts
Top