Receiving ECM signal, linear solenoid type electronic EGR actuator operates Electric EGR control valve directly.
ECM performs EGR system feed back control with the information of measured mass air flow (The role of MAFS in diesel engine is different from gasoline engine. Fuel injection quantity is decided by MAFS signal in gasoline engine.)
When EGR gas(contains no oxygen) flowing into combustion chamber increases, the air passing through AFS(contains oxygen) decreases. Thus, with the output signal change of AFS accompanied by Electric EGR control valve actuation, ECM determine the amount of recirculated EGR gas quantity.
NOx is produced from the reaction of nitrogen and oxygen.
Controlling EGR gas(contains no oxygen) which is recirculated to combustion chamber, if least intake air required for complete combustion flows into combustion chamber, NOx decreases because there is no supplementary oxygen to react with nitrogen.
P0402 is set when EGR governer deviaton is above the upper limit value for more than 5 sec. This code is due to open or short to battery in EEGR actuator circuit or internal open in EEGR component.
Item | Detecting Condition | Possible Cause | ||
DTC Strategy | ● Signal monitoring | ● EGR actuator stuck ● EGR actuator component ● Air leakage of intake line | ||
Enable Conditions | ● Engine running | |||
Threshold Value | ● Real value - Target value < lower specified air amount value | |||
Diagnostic Time | ● 5 sec. | |||
Fail Safe | Fuel Cut | NO | ||
EGR Off | YES | |||
Fuel Limit | NO | |||
Check Lamp | YES | |||
Electric EGR control valve component resistance | Electric EGR control valve operating Hz | Electric EGR control valve operating duty |
14.7 ~ 16.1Ω (20℃) | 142Hz | 5%(closed)~39%(opened) |
The output of approx. 10% duty is mainly for the diagnosis of EEGR actuator circuit than actuating EEGR.
