Recently i found that mine 93 civic Cel light on once RPM>3000.I tried to jump the ECU, i found that it is code 48-LAF sensor. Does this mean the o2 sensor is not working properly? But why the cel light only on once the RPM >3000?
Does the CEL turn back off if the RPMs drop below 3000?
And the Code 48 is triggered when the ECU is no longer receiving the voltages expected from the LAF/L1H1/O2 sensor.
If you can replace the O2 sensor, but first make sure that everything else is working correctly on the motor. Good to eliminate anything that could be causing the O2 to foul up first.
Just because the light isn't on doesn't mean the ECU doesn't have stored codes. You retrieve them by jumpering the two pin diagnostic plug in the green cover near the front passenger's right kick panel.
Linear Mode
