5 minute read
MID 128, PID 100 Oil pressure sensor
MID 128, PID 100 Oil pressure sensor (engine)
MID 128: Engine control unit Fault code
FMI 0:The sensor value is valid but exceeds the normal working range. FMI 1:The sensor value is valid but is less than the normal working range. FMI 3:The voltage exceeds the normal value or is short circuited to higher voltage. FMI 4:The voltage is less than the normal value or is short circuited to battery negative. FMI 5:The current is less than the normal value or is open circuited. FMI 6:The current is greater than the normal value or is short circuited to battery negative. FMI 9:Abnormal updating rate.
FMI Fault code explanation
0 Too high lube oil pressure 1 Too low lube oil pressure 3, 4, 5, 6, 9 Faulty sensor / Faulty sensor circuit
Fault indication
Warning is displayed in the tachometer/display. FMI 1: Oil pressure indication in alarm display shows red. Audible warning.
FMI 0, 3, 4, 5, 6, 9:A red lamp flashes in the alarm display.
Symptom
Engine power is limited.
Connector (36 pin)
Circuit description
Sensor is an active sensor, i.e. the sensor must have operating voltage. Pin 9 on the engine control unit (EDC7) provides pin 1 on the sensor with an operating voltage of +5 Volt. Pin 4 on the monitor is connected to battery negative via pin 19 on the control unit. The output signal from the pressure sensor (pin 2 on sensor to pin 33 on the control unit) is a voltage signal which is proportional to the oil pressure (after the oil filters).
Fault tracing
FMI 0: Too high lube oil pressure
Conditions for fault code
Oil pressure exceeds 600 kPa (6,0 bar).
Possible reason
● Lube oil contaminated or far too thick (high viscosity). ● Fault in reduction valve or pressure relief valve. ● Fault in sensor.
Suitable action 1
Check the oil level in the engine.
2
Check that the oil filters are not blocked. Change oil filters.
3
Check that no leakage occurs.
4
Check the sensor by checking the engine oil pressure. Please, refer to “Lubrication system, Workshop manual”.
FMI 1: Too low lube oil pressure
Conditions for fault code
Oil pressure is less than 50–250 kPa (0.5–2.5 bar) at engine speeds up to 4,000 rpm.
Possible reason
● Too low lube oil level. ● Oil contaminated, viscous or too thin. ● Fault in bypass valves. ● Worn oil pump. ● Blocked oil suction pipe. ● Blocked oil filter.
Suitable action 1
Check the oil level in the engine.
2
Check that the oil filters are not blocked. Change oil filter.
3
Check that no leakage occurs. Please, refer to Workshop manual.
4
Check the sensor by checking the engine oil pressure. See “Lubrication system, Workshop manual”.
Conditions for fault code
Voltage on pin 33 on engine control unit (EDC7) exceeds 4.95 Volt.
Possible reason
● Short circuited sensor signal cable to battery voltage or 5V voltage. ● Open circuit in sensor signal cable. ● Open circuit in sensor negative cable. ● Open circuit, all cables missing. ● Fault in sensor.
Suitable action 1
Check the cables and the connectors between the sensor and the engine control unit (EDC7).
2
Check sensor.
Conditions for fault code
Voltage on pin 33 on engine control unit (EDC7) is less than 0.37 Volt.
Possible reason
● Open circuit in 5V sensor supply cable. ● Short circuited sensor signal cable to battery negative. ● Fault in sensor.
Suitable action 1
Check the cables and the connectors between the sensor and the engine control unit (EDC7).
2
Check sensor.
FMI 5: Abnormally low current or open circuit has been detected.
Conditions for fault code
Voltage on pin 10 on engine control unit (EDC7) exceeds 5.05 Volt.
Possible reason
● Short circuited sensor supply cable to battery voltage. ● Fault in sensor.
Suitable action 1
Check the cables and the connectors between the sensor and the engine control unit (EDC7).
2
Check sensor.
Conditions for fault code
Voltage on pin 10 on engine control unit (EDC7) is less than 4.50 Volt.
Possible reason
● Short circuited 5 V sensor supply cable to battery negative. ● Fault in sensor.
Suitable action 1
Check the cables and the connectors between the sensor and the engine control unit (EDC7).
2
Check sensor.
FMI 9
Conditions for fault code
Abnormal updating rate.
Possible reason
● Fault in sensor. ● AD conversion failed (fault in engine control unit,
EDC7).
Suitable action 1
Check sensor.
2
Change engine control unit (EDC7).
Measurements
Special tools: 9812519, 885675
Negative cable
1
NOTE! Cut the current with the main switch.
2
Remove the connector from the sensor. Connect adapter cable 885675 to cable harness connector to engine control unit (EDC7).
3
Use multimeter 9812519 to do resistance measurement against the engine control unit.
Measurement points Nominal value
4 – Battery negative* R ≈ 0 Ω
*Note. Battery negative (–) on alternator or starter motor.
Signal cable
1
NOTE! Cut the current with the main switch.
2
Remove the connector from the sensor. Connect adapter cable 885675 to cable harness connector to engine control unit (EDC7).
3
Use multimeter 9812519 to do resistance measurement against the engine control unit. Note. Measurement is done to eliminate short circuiting or breaks in the cable to the engine control unit.
Measurement points Nominal value 2 – Battery negative* R ≈ 500–900 kΩ
*Note. Battery negative (–) on alternator or starter motor.
Supply cable
1
Remove the connector from the sensor. Connect adapter cable 885675 between sensor and engine control unit (EDC7).
2
Turn the main switches on. Turn the starter key to position I (driving position).
3
Use multimeter 9812519 for voltage measurement.
Measurement points Nominal value
1 – 4 U ≈ 5 V
Checking the oil pressure sensor*
*Note. Combined sensor, oil pressure and oil temperature (engine).
Special tools: 9812519, 885675
1
NOTE! Turn the starter key to position 0.
2
Remove the connector from the sensor. Connect adapter cable 885675 between sensor and engine control unit (EDC7).
3
Turn the starter key to position I (driving position).
4
Use multimeter 9812519 for voltage measurement.
Measurement points Nominal value
2 – 4 U ≈ 0,5 V*
Output voltage, V
Lube oil pressure, kPa
Component specification
Working range ............................0–700 kPa (0–7 bar) Supply voltage .................................. 5,00 ±0,25V DC
Nominal output voltage at 25°C and power supply voltage 5.00V DC: 0,5V DC at ...........................................0 kPa (0 bar)* 4,5V DC at ........................................700 kPa (7 bar)*
*Note. At normal atmospheric pressure.
