Charge Air Pressure Sensor; Fuel Rail Pressure Sensor - Yanmar BY Series Service Manual

ELECTRICAL AND ECU

Charge Air Pressure Sensor

This sensor measures the charge air pressure as
absolute value (charge air pressure + atmospheric
pressure). It is mounted on the charge air pipe and
is sealed by an O-ring.
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.)
If this sensor is defective, the following P-codes
may be generated:
• P0238 - short circuit to B+
• P0237 - no connection / short circuit to ground
• P0236 - no plausibility
Test Values
Note: Pressure is kPa (absolute)
• Relation to supply voltage:
Vout = (2/875 x pressure value - 1/70) x supply
voltage
Examples:
• At 5V supply voltage and atmospheric pressure
(98 kPa), Vout is approximately 1.04 V
• At 5V supply voltage and 200 kPa (absolute),
Vout is approximately 2.21 V
Figure 12-19
1 – Pin 1 - 5V (ECU pin 1/39)
2 – Pin 2 - Ground (ECU pin 1/80)
3 – Pin 3 - Out (ECU pin 1/54)
12-22
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Fuel Rail Pressure Sensor

This sensor measures the fuel pressure in the fuel
rail. The values are used by the ECU for fuel
quantity regulation and fuel pressure regulation. It
is mounted on the front of the fuel rail. The ECU
supplies 5V and ground.
Results of Failed Sensor
Failure of the sensor results in:
• Default value in the ECU
• Limitation of the injection rate (See Engine Faults
and Torque Limitations on page 13-3.)
IMPORTANT
If a fault code is set, check the fuel supply
and delivery first!
If this sensor is defective, the following P-codes
may be generated:
• P0088 - fuel rail pressure out of range
• P0087 - fuel rail pressure out of range
• P0089 - fuel rail pressure out of range
• P0090 - fuel rail pressure out of range
• P0193 - no connection / short circuit B+
• P0192 - short circuit to ground
Test Values
• At 0 bar (0 psi) (relative): 0.5 V
• At 1800 bar (26, 107 psi) (relative): 4.5 V
Figure 12-20
1 – Pin 1 - Ground (ECU pin 1/78)
2 – Pin 2 - Out (ECU pin 1/56)
3 – Pin 3 - 5V (ECU pin 1/30)
BY Service Manual
Component Tests
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