Circuit description
A
valve
is installed in the oil filter bracket which opens
or closes the oil supply for piston cooling, depending
on oil pressure. If the oil pressure is below 250 kPa
(TAD950-952VE) or 300 kPa (TAD1250-1252VE), the
valve closes the oil supply for piston cooling.
The piston cooling pressure is monitored by a pressure
switch. The output signal from the pressure switch, pin
1 to the engine control unit, can only have two distinct
positions, on/off. The switch is supplied with current
from the engine control unit pin 10. A pre-set pressure
limit of 150 kPa determines when it switches on. The
switch opens if the pressure exceeds this value.
At idle, the switch can be closed without a fault code
being set.
Component specification
Switching point: 150kPa = 1.5bar
Supply voltage: 12-24 VDC
Measurements
Checking negative cable, piston cooling oil tempera-
ture switch page 170
Checking supply cable, piston cooling oil temperature
switch page 171
10
14
A
P
2
1
EMS2
SB
GR / R
SB
B
P0013511
A Connector B
B Piston cooling pressure
30-2 Fault Tracing
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