Does my car or Truck have Wideband or Narrowband O2 Sensors?

Wideband O2 Sensors - most Japanese cars, trucks & German made cars/trucks
Narrowband O2 Sensors - US built cars, except newer models 2009 and newer.
If you have a 4 wire O2 sensor it is a narrowband, unless you have a Toyota.
Toyota's have a 4 wire WideBand O2 Sensor. 5 and 6 wire O2 sensors are wide band.
ALL down-stream sensors are narrowband, no matter which vehicle.

Misnomer - O2 sensors do not sense oxygen, they only react to gas fumes.
So if you complete the burn with HHO gas from water, the exhaust is clean
the o2 sensor will sense a lean burn and tell the
ECM to "Enriched the fuel ECM" give it more gas, lets heat up that engine back up.
These circuits stop that enrichment move and you save on fuel costs.
Most diesel engines have no O2 sensors, except the newer semi truck engines.

Always check and make sure before ordering, for not all cars follow a rule, as above.

One easy method to find if you car uses Wideband o2 sensors or narrowband o2 sensors.

Go to


2. Now, Click on "REPLACEMENT PARTS" TAB to go to a new page

3. "SELECT A CATEGORY" (You should see a long list of parts)


5. Then "OXYGEN SENSOR"; a selection of sensors for your vehicle appears
You will see Part Number, Warranty and then "APPLICATION:" and you will have your choice of either a Down-Stream Sensor, or an Up-Stream Sensor.

ALL down-stream sensors are narrowband, no matter which vehicle.

We want to know what your "UP-STREAM SENSOR" is! Find the first one on the list and click on it to go to detail page. Scroll down past the "Features and Benefits" section, and look for "OXYGEN SENSOR TYPE" It will tell you if it is Narrow-Band or Wide Band (heated or un heated doesn't matter).

Back to Daron's Circuits

Vol's are easier to install, just 4 wires and takes about 30 minutes to install.
Daron's Circuits take longer to install 2 to 8 hours, but more control and more MPG savings
You can monitor the inputs, as Vol FS2-HHO Edition does it for you.

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Hydrogen Garage LLC • California • USA

Search Engine Submission - Addie updated 6/30/2018