Specs Location of 02 sensor

Hi Chuck:
The sensors are located in the exhaust system. On some vehicles one sensor is located up at the exhaust manifold and the other sensor is located down at the catalytic converter. On other vehicles both sensors are located down at the catalytic converter.

Testing - 2000-2003
Perform a visual inspection of the sensor as follows:

1. If the sensor tip has a black/sooty deposit, this may indicate a rich fuel mixture.
   
2. If the sensor tip has a white, gritty deposit, this may indicate an internal coolant leak.
   
3. If the sensor tip has a brown deposit, this could indicate excessive oil consumption.
   
4. Warm the engine until the coolant temperature reaches operating temperature.
   
5. Run the engine at idle speed.
   
6. Connect a voltmeter between terminal 4 (grn/brn) and ground.
   
7. Increase and decrease the engine speed quickly several times.
   
8. Specification should be 0-1.0 volt.
   NOTE The rear sensor voltage does not fluctuate as quickly as the front sensor.
   
9. If not as specified, inspect the on-board diagnostic system, exhaust system, intake manifold system and fuel line pressure.
   
10. If all systems are normal, replace the sensor.
    
11. To check the heater, be sure that the ignition switch is OFF.
    
12. Disconnect the sensor connector from the wire harness, if not already done.
    
13. Connect an ohmmeter between terminals 1 and 3. Measure the resistance.
    
14. Specification should be approximately 2-4 ohms at 68 F degrees.
    
15. If not as specified, replace the sensor.