Inspecting/Cleaning Egr Related Components - Yanmar 3TNV82A-B Service Manual

EGR system
Inspecting/cleaning EGR related
components
EGR Valve
Each EGR valve has four built-in coils. The power
to each of the four coil is either ON or OFF at any
given time. Depending on which coil is ON and
which coil is OFF, the step motor rotates to
determine the valve lift. The power to each coil is
turned ON/OFF by the E-ECU based on the engine
speed and fuel injection rate. The resistances of
these coils should be as specified below when
measured between each pair of pins shown. If any
of the actually measured values is beyond the
standard range, replace the entire EGR valve
assembly.
(1)
1 – EGR valve connectors
Figure 6-157
Standard value
Terminal
1 - 2
2 - 3
4 - 5
5 - 6
Note: The higher the temperature, the higher
the coil resistance. Therefore, wait for the
EGR valve to return to normal state
before measuring the resistances.
TNV DI Service Manual
Ω
Resistance ( )
15 ± 2
at 20 °C
EGR valve operation checks
1. After removing each EGR valve from the
engine, connect the valve with the connector.
2. Connect the valve to the battery's minus (-)
terminal.
3. Turn on the key switch.(Note that turning on the
key switch causes the E-ECU to check whether
the valve functions properly by opening and
shutting it.)
4. From the exhaust gas inlet, visually check
whether the valve operates correctly.
Note: If the EGR valve fails to smoothly
operate, replace the entire valve
assembly with new one.
Note: If the EGR valve does not respond at all,
check whether there exists a voltage
(EGR valve signal) between the
connector pins. If the voltage is within the
standard range, then replace the entire
valve assembly with new one.
IMPORTANT
Alternatively, you can remove the EGR pipe
from the engine and check the valve
operation through the gas inlet window,
instead of removing the EGR valve from the
engine.
ENGINE
6-105