Fuel Temperature Sensor - Yanmar BY Series Service Manual

ELECTRICAL AND ECU
Figure 12-15
1 – Pin 1 - Glow plug No. 1
2 – Pin 2 - Glow plug No. 2)
3 – Pin 3 - Glow plug No. 3)
4 – Pin 4 - Glow plug No. 4)
5 – Pin 5 - Glow plug No. 5)
6 – Pin 6 - Glow plug No. 6)
7 – Pin 12 - Signal of measured value
(ECU pin 1/68)
8 – Pin 6 - Ground (ECU pin 1/70)
9 – Pin 5 - 12V (Fuse F5)
Connector X3
The control signals travel via connector X3. If the
glow control unit is not installed, connector X3 must
be protected by a cover.
12-20
0004172

Fuel Temperature Sensor

This sensor measures the temperature of the fuel
being supplied to the high-pressure fuel pump. It is
a NTC (negative temperature coefficient) type
sensor. It is mounted in the fuel line just upstream
from the high-pressure fuel pump.
The sensor output is used by the ECU for:
• Protecting the engine from overheating
• Calculation of the injection rate
• Calculation of the rate of the fuel pump
Results of Failed Sensor
Failure of the sensor results in:
• Limitation of the injection rate (See Engine Faults
and Torque Limitations on page 13-3.)
• Destruction of the sensor if short circuit to B+
If this sensor is defective, the following P-codes
may be generated:
• P0182 - short circuit to B+
• P0183 - No connection / short to ground
Test Values
• Resistance at -20°C (-4°F): 20 - 24 k-ohm
• Resistance at 0°C (32°F): 16.5 - 8 k-ohm
• Resistance at 20°C (68°F): 2.4 - 3.2 k-ohm
• Resistance at 120°C (248°F): 0.5 - 0.6 k-ohm
(1)
Figure 12-16
1 – Pin 1 - Ground (ECU pin 1/11)
2 – Pin 2 - Out (ECU pin 1/83)
BY Service Manual
Component Tests
(2)
0004168