Downstream O2 Sensor questions

2002 DODGE DAKOTA
109 MILES
Avatar
JFLS45
  • MEMBER
  • 1 POST
2002 Dodge Dakota, 3.9L V6, 109K Miles

Downstream O2 Sensor questions
I ran a OBD Scan program from my netbook today and observed the following:
Can someone who knows how O2 sensors work explain which downstream sensor is working correctly, see the attached photo.
This photo shows the O2 sensors after the vehicle has been warmed up to normal operating temp. The downstream are the two on the bottom. Could this be causing a stutter or slight roughness in engine?
Image (Click to enlarge)
Attached Media
Dec 4, 2011 at 3:49 AM
Advertisement
Avatar
CARADIODOC
  • CERTIFIED EXPERT
  • 34,306 POSTS
The left one is normal. The right one indicates no change is taking place in the exhaust gas as it passes through the catalytic converter. That converter needs to be replaced if everything else is working properly.

Oxygen sensors don't typically cause running problems. They only report what they see, but the Engine Computer does use that information to make ongoing adjustments to the fuel / air mixture.
Dec 4, 2011 at 3:57 AM