Stratus L4-2.4L DOHC (1995)
Oxygen Sensor: Testing and Inspection
Oxygen Sensor Heater Circuit Test
NOTE: Use an ohmmeter to test the heating element of the oxygen sensors.
1. Disconnect the electrical connector from each oxygen sensor.
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The white wires in the sensor connector are the power and ground circuits for the heater elements.
2. Connect the ohmmeter test leads to terminals of the white wires in the heated oxygen sensor connector.
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Replace the heated oxygen sensor if the resistance is not between 5 and 7 ohms.
NOTE: This test should be performed only after basic inspection, and ignition and fuel systems inspections are passed.
NOTE: Only use a high input impedance Digital Volt Ohm Meter (DVOM) when testing components on computerized vehicles.
CAUTION: Verify DVOM is set to read VOLTS ONLY (not ohms). Verify external voltage is not applied to the sensor lead, as damage to the sensor
may occur.
1. Make sure the vehicle is at normal operating temperature. Run the engine at 2500 rpm for 3 minutes with the transmission in PARK (A/T) or
NEUTRAL (M/T).
2. With engine OFF, connect the negative lead of the DVOM to engine ground. Set the DVOM to read DC VOLTS. Disconnect the oxygen sensor
connector. Connect the positive lead of the DVOM to the oxygen sensor.
3. Create a full lean condition, by removing a large vacuum hose, for 10 seconds. Voltage should decrease to 0.2 volt or less and remain there.
4. Create a full rich condition, by introducing propane into intake manifold, for 10 seconds. Voltage should increase to 0.8 volt or less and remain
there.
5. Verify that engine is at operating temperature and O2 sensor heating element (if equipped) is functioning. See, sensor heating element test.
6. If engine is at operating temperature and heating element passes, but the sensor fails to vary according to the test steps above, the sensor is
defective.
7. Connect the oxygen sensor and clear codes.
NOTE: Complete testing for this system or component can be found at the system level. See: Testing and Inspection/Diagnostic Trouble Code Tests
and Associated Procedures/Manufacturer Code Charts/Trouble Code (TC) Tests/DTC Test - CODE TO TC TEST CHART (Checking for Trouble
Codes)
