Colt L4-1795cc 1.8L SOHC (1993)
Continuity:
Should exist
Osciloscope Test
OSCILLOSCOPE TEST
1. Connect scope pickup probe to the sensor terminal A3.
2. Warm engine to operating temperature and keep it running at 2,000 RPM, check the waveform on the scope. If scope pattern is not as depicted in
image, the sensor may be bad or there could be a fuel mixture problem. Refer to diagnosis by symptom for further system troubleshooting before
replacing the assembly.
HARNESS TEST
1. Disconnect the oxygen sensor and the ECM connectors.
2. Using an Ohmmeter, check for continuity between the ECM harness connector terminal 56 and the oxygen sensor harness connector terminal A3.
Continuity:
Should exist.
3. Using an Ohmmeter, check for continuity (short) to ground between the ECM harness connector terminal 56 and the oxygen sensor harness
connector terminal A3.
Continuity:
Should not exist.
4. Using an Ohmmeter, check for continuity between the ECM harness connector terminal 72 and the oxygen sensor harness connector terminal A1.
Continuity:
Should exist.
5. Using an Ohmmeter, check for continuity between the oxygen sensor harness connector terminal A4 and ECM harness connector terminal 105.
Continuity:
Should exist.
If any of the previous tests produce unsatisfactory results, the harness will need to be repaired or replaced. Once repairs have been completed,
clear the trouble codes and road test the vehicle to confirm that the repair has corrected the problem and the code doesn't return.
If the same trouble code reoccurs, it is possible that there is an intermittent failure of the component or the ECM. Check for looseness at all
harness junctions and test for an intermittent failure.
Rear Oxygen Sensor Test
