Starting Mode; Closed Loop; Acceleration Mode; Deceleration Mode - SSANGYONG Actyon 2012.12 Manual

02-6

1) Starting Mode

When the ignition is turned ON, the ECM turns the fuel pump relay on for 1 second. The fuel pump then
builds fuel pressure. The ECM also checks the Engine Coolant Temperature (ECT) sensor and the
Throttle Position (TP) sensor and determines the proper air/fuel ratio for starting the engine. This ranges
from1.5 to 1 at -36 °C
temperature. The ECM controls the amountof fuel delivered in the starting mode by changing how long
the fuel injector is turned on and off. This is done by ''pulsing" the fuel injectors for very short times.
2) Run Mode
The run mode has two conditions called ''open loop" and ''closed loop".
3) Open Loop
When the engine is first started and it is above 690 rpm, the system goes into "open loop" operation. In
"open loop", the ECM ignores the signal from the HO2S and calculates the air/fuel ratio based on inputs
from the ECT sensor and the MAF sensor. The ECM stays in "open loop" until the following conditions
are met:
- The O2 has a varying voltage output, showing that it is hot enough to operate properly.
The ECT sensor is above a specified temperature (22.5 °C).
-
- A specific amount of time has elapsed after starting the engine.

4) Closed Loop

The specific values for the above conditions vary with different engines and are stored in the
Electronically Erasable Programmable Read-Only Memory (EEPROM).
When these conditions are met, the system goes into "closed loop" operation. In "closed loop", the ECM
calculates the air/fuel ratio (fuel injector on- time) based on the signals from the O2 sensors. This allows
the air/fuel ratio to stay very close to 14.7 to 1.

5) Acceleration Mode

The ECM responds to rapid changes in throttle position and airflow and provides extra fuel.

6) Deceleration Mode

The ECM responds to changes in throttle position and airflow and reduces the amount of fuel. When
deceleration is very fast, the ECM can cut off fuel completely for short periods of time.
(-33 °F) coolant temperature to 14.7 to 1 at 94 °C (201 °F) coolant