Receiving ECM signal, linear solenoid type electronic EGR actuator operates EEGR valve directly.ECM performs EGR system feed back control with the information of measured mass air flow (The role of AFS in diesel engine is different from gasoline engine. Fuel injection quantity is decided by AFS 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 EEGR actuator 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 oxyger) 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.
P0490 is set when excessive current is detected in EEGR actuator circuit for more than 0.5 sec.. This code is due to short to battery in EEGR actuator control circuit or internal short in EEGR component.
Item | Detecting Condition | Possible Cause | ||
DTC Strategy | ● Signal monitoring | ● EGR actuator circuit ● EGR actuator component | ||
Enable Conditions | ● Engine running | |||
Threshold Value | ● Short to battery | |||
Diagnostic Time | ● 0.5 sec. | |||
Fail Safe | Fuel cut | NO | ||
EGR Off | YES | |||
Fuel Limit | NO | |||
Check Lamp | YES | |||
The output of approx. 10% duty is mainly for the diagnosis of EEGR actuator circuit than actuating EEGR.
EGR actuatorcomponent resistance | EGR actuator operating Hz | EGR actuator operating duty |
7.3~ 8.8Ω (30℃) | 142Hz | approx.10%(closed)~40%(opened) |
Connect Scantool to Data Link Connector (DLC).
Warm engine up to normal operating temperature.
Turn "OFF" electrical devices and A/C.
Monitor "AIR MASS PERCYLINDER" parameter on the Scantool.
Specification : When EEGR actuator does not operate 5% duty) at idle : 450mg/st ± 50 mg/st
When EEGR actuator operates(Approx. 50% duty) at idle : 300mg/st ± 50 mg/st
EEGR actuator operates as decelerating after rapid acceleration when idle EEGR does not operate, EEGR actuator duty rises to approx. 45% at operating condition. This controlling process lasts for about 56 sec. then EEGR actuator turns "OFF" (duty 5% ).
Electrical systems consist of a lot of harness and connectors, poor connection of terminals can cause various problems and damge of component.
Perform checking procedure as follows.
Check damage of harness and terminals : Check terminals for contact resistance, corrosion and deformation.
Check connecting condition of ECM and component connector : Check terminal seperation, damage of locking device and connecting condition between terminal and wiring.
Disconnect the pin which requires checking at male connector and insert it to the terminal at female connector for checking connecting condition. ( after checking, reconnect the pin at correct position. )
Is the problem found?
▶ Repair the trouble causing part and go to "Verification of Vehicle Repair".
▶ Go to "Power Circuit Inspection".
Check power circuit voltage
IG KEY "OFF", ENGINE "OFF"
Disconnect EEGR actuator connector
IG KEY "ON"
Measure the voltage of terminal 2 of EEGR actuator connector.
Specification : 11.5V~13.0V
Is the measured voltage within the specification?
▶ Go to "Control Circuit Inspection".
▶ Repair E/R JUNCTION BOX 15A INJ SNSR1 fuse and related circuit and go to "Verification of Vehicle Repair".
Check control circuit monitoring voltage
IG KEY "OFF", ENGINE "OFF"
Disconnect EEGR actuator connector.
IG KEY "ON"
Measure the voltage of terminal 1 of EEGR actuator connector.
Specification : 3.2V~3.7V
Is the measured voltage within the specification?
▶ Go to "Component Inspection".
▶ When voltage is not detected : Go to "2. Check open in control circuit" as follows.
▶ When high voltage is detected : Repair short to battery and go to "Verification of Vehicle Repair".
Check open in control circuit
IG KEY "OFF", ENGINE "OFF"
Disconnect EEGR actuator connector and ECM connector
Check continuity between EEGR actuator terminal 1 and ECM connector (C244-A) terminal 59.
specification : Continuity ( below 1.0Ω )
Is the measured resistance within the specification?
▶ Repair short to ground and go to "Verification of Vehicle Repair".
▶ Repair open in control circuit and go to "Verification of Vehicle Repair".
Check EEGR actuator component resistance
IG KEY "OFF", ENGINE "OFF".
Disconnect EEGR actuator connector.
Measure the resistance between EEGR actuator component terminal 1 and 2.
Specification : 7.3~ 8.8Ω (30℃)
Is EEGR actuator component resistance within the specification?
▶ Go to "Verification of Vehicle Repair".
▶ Replace EEGR actuator and go to "Verification of Vehicle Repair".
After a repair, it is essential to verify that the fault is corrected.
After connecting Scantool select "DIAGNOSTIC TROUBLE CODES(DTCs)" mode.
Clear recorded DTC using Scantool.
Drive the vehicle within DTC "Enable conditions" in "General information".
After selecting "DIAGNOSTIC TROUBLE CODES(DTCs)" mode and check if DTC is recorded again.
Are any DTCs recorded ?
▶ Go to the DTC guide of recorded NO. in Scantool.
▶ System operates within specification.
