Yugo L4-1300cc 1.3L (1991)
Check Engine Lamp: Description and Operation
The check engine lamp should always illuminate with the ignition switch is in the Run position and the engine is Off. When the engine is started, the
check engine lamp should turn Off immediately indicating no fault codes have been stored in the ECU. If the lamp turns Off 3 seconds after the engine is
started at least one code, known as a secondary fault is stored in the ECU. This type fault will not affect exhaust emissions. If the check engine lamp
stays On after the engine is started, at least one code known as a static fault has been stored in the ECU. This type fault could affect any part of the
electronic engine control system. Static faults will also cause the ECU to use pre-set values to control engine operation. Only when the fault has been
eliminated will the ECU return control to the sensors for operating parameters.