Intake and exhaust manifold pressure in diesel engine is equal to atmospheric pressure or bigger than it.
So it is difficult to recirculate exhaust gas within short time because the pressure difference of intake and exhaust manifold is not enough.
ACV(Air Control Valve) is installed before intake manifold.
This is shut when EGR is operated and the pressure difference come to be bigger. So EGR gas recirculation come to be easy.
ACV is consist of DC motor and position senser.
P2101 is set when ACV position can not follow the target position of ECM more than 1 sec.
Item
Detecting Condition
Possible Cause
DTC Strategy
Signal monitoring
ACV actuator
Enable Conditions
Engine running
Threshold Value
Actuator temperature is high.
The differece of virgin and new learnt value is over limited value.
Diagnostic Time
1 sec.
Fail Safe
Fuel cut
NO
-
EGR Off
YES
Fuel Limit
Check Lamp
ON
ACV actuator resistance
23 O (between 1,3 terminal)
Fig.1) Signal at idle
Fig.2) Signal when Key "ON" ? "OFF"