Laser FWD L4-1997cc 2.0L DOHC Turbo (1993)
1. Connect scope pickup probe to the sensor terminal 1.
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.
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 ECU. Check for looseness at all harness
junctions and test for an intermittent failure.
Harness Inspection
Step 1
Step 2
Step 3
TROUBLESHOOTING HINTS
Even if the Oxygen sensor is troubled, the driveability is hardly influenced. However hazardous components (HC, CO, NOx) in the exhaust gas
increase since the air-fuel mixture ratio is not closed loop to the control.
