Electronically controlled diesel engine has high fuel efficiency therefore, heat loss through wall or head of cylinders after combustion is much more less than that of gasoline engine. This characteristic increases power generation and fuel efficiency however it keeps engine coolant from rising fast on the other hand. so, warming efficiency in winter decreases.
ECM controls the heater relay1 and 2 under conditions which the coolant temperature is below 70℃ and engine speed is over 700 rpm.
※ Prohibition conditions of heater relay control : Coolant temperature above 70℃, Engine speed below 700 rpm.
Item | Detecting Condition | Possible Cause | ||
DTC Strategy | ● Voltage monitoring | ● Heater Relay circuit ● Heater Relay component | ||
Enable Conditions | ● IG KEY "ON" | |||
Threshold Value | ● Short to GND, Short to battery | |||
Diagnostic Time | ● 1.0 sec | |||
Fail Safe | Fuel Cut | NO | ||
EGR Off | NO | |||
Fuel Limit | NO | |||
MIL | NO |