Heating combustion chamber, glow plug increases fuel ignitibility and makes fuel in the foggy state easily when engine is cold. Thus, glow plug makes engine starting easily and decreases exhaust gas produced just after turning engine on when engine is cold.
ECM controls operation and operating duration of glow plug relay which supplies power to glow plug with ECTS signal, battery voltage and IG KEY ON signal.
Through glow lamp in cluster, ECM let drivers know if glow plug is ON.
P0542 is set when excessive current is detected in Air Heater relay control circuit for more than 1 sec.. This code is due to short to battery in Air Heater relay control circuit or internal short in relay component.
Item
Detecting Condition
Possible Cause
DTC Strategy
? Voltage monitoring
? Air Heater relay circuit
? Air Heater relay component
Enable Conditions
? IG KEY "ON"
Threshold Value
? Short to battery
Diagnostic Time
? 1.0 sec.
Fail Safe
Fuel Cut
NO
EGR Off
Fuel Limit
Check Lamp