XT 4WD F4-1781cc 1.8L SOHC (1990)
Engine Control Module: Description and Operation
O2 Monitor Lamp
LED Oxygen Monitor Lamp
PURPOSE
Indicates ECU ID codes and trouble codes.
LOCATION
On the ECU.
OPERATION
When the system is in "U-CHECK" mode and the "CHECK ENGINE" lamp is off, the O2 monitor lamp will flash the ID code. When the
"CHECK ENGINE" lamp is on or when the system is in the "D-CHECK" mode, the monitor lamp will flash trouble codes.