* Upstream Sensor(s): Located in the exhaust manifold or close to it, before the catalytic converter. There's usually one upstream sensor, but some configurations might have two (one for each exhaust bank if it's a V-8). This sensor monitors the exhaust gases *before* the catalytic converter.
* Downstream Sensor(s): Located in the exhaust system after the catalytic converter. This sensor monitors the exhaust gases *after* the catalytic converter, primarily to check the converter's efficiency. Again, there might be one or two depending on the engine.
To find the exact location:
1. Consult your owner's manual: This is the best place to start. The manual should have diagrams showing the location of the sensors for your specific engine.
2. Use a repair manual: A Haynes or Chilton repair manual for your year and model of Dodge Ram will have detailed diagrams and descriptions of sensor locations.
3. Online resources: Search online for "2001 Dodge Ram [engine size] oxygen sensor location." You might find images or forum posts from others who have worked on the same truck.
Caution: The exhaust system gets very hot. Allow the engine to cool completely before attempting to locate or replace the oxygen sensors. Always use appropriate safety gear, such as gloves and eye protection.
