Geely EC718 2009 Workshop Manual page 106

2-24 Control System JL4G18-D Engine
2.2.3.3 Fault Self-Diagnostic and Protection
Function
In order to discover the engine electronically controlled
gasoline injection system fault in time, and maintain the vehicle
basic driving ability when a fault occurs, ECM has a fault
diagnostic and self-protection function. ECM is equipped with
a dedicated self-diagnostic circuit. When the engine is running,
ECM continuous monitors various parts. Once ECM detects an
abnormal situation, it will store the fault signal in memory, and
displays DTC code.
In order to prevent vehicle can not be driven due to the sensor
malfunction. ECM uses pre-stored sensor signals to continue
to control engine operation.
For actuators, in order to prevent their failure affect safety, ECM
can take measures to ensure the engine safety. At this point,
ECM will send out warning signals and stop fuel injection.
In addition, ECM is also equipped with an emergency circuit.
When the emergency control circuit receives an abnormal
signal, ECM will enable the backup program. The fuel injection
amount and ignition timing will be controlled according to the
original set-up program, to maintain the vehicle basic driving
ability.
EC718/EC718RV EC715/EC715RV 10/2009