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Volvo Engine Control Unit Fault Codes

May. 18, 2018

MID 128, PID 97 Water in fuel indicator


MID 128: Engine control unit

 

 

FMI 0 – Data valid but above normal operational range

Fault code explanation:

Water in Fuel

Fault indication:

DCU: Engine warning in DCU display.

CIU: Flash code

Flash code

Electrical fault: 2.9

Value fault: 2.1

Symptom:

None

Conditions for fault code:

Water in the fuel trap has been detected.

Suitable action:

1 Empty the water trap.

2 Check function of water in fuel switch

Measurements:

• Checking water in fuel switch page 119

 

 

FMI 3 – Voltage above normal or short circuit to higher voltage

Fault code explanation:

Faulty sensor / Faulty circuit

Fault indication:

DCU: Engine warning in DCU display.

CIU: Flash code

Flash code

Electrical fault: 2.9

Value fault: 2.1

Symptom:

None

Conditions for fault code:

The voltage signal on B8 is too high.

Possible reason:

The cable connected to B8 is short circuited to battery voltage.

Suitable action:

1 Check cable harness and connectors between water in fuel switch and

EMS 2.

Measurements:

• Checking supply cable, water in fuel switch page 118

• Checking negative cable, water in fuel switch page 118

 

 

FMI 4 – Voltage below normal or short circuit to lower voltage

Fault code explanation:

Faulty sensor / Faulty circuit

Fault indication:

DCU: Engine warning in DCU display.

CIU: Flash code

Flash code

Electrical fault: 2.9

Value fault: 2.1

Symptom:

None

Conditions for fault code:

The voltage signal on B8 is too low.

Possible reason:

• Short circuit between both cables to the water in fuel switch.

• The cable connected to B8 is short circuited to battery negative.

Suitable action:

1 Check cable harness and connectors between water in fuel monitor and

EMS 2.

Measurements:

• Checking supply cable, water in fuel switch page 118

• Checking negative cable, water in fuel switch page 118

 


Circuit description

A switch is located in the water trap under the fuel filter. Its task is to detect whether there is water in the fuel. The switch senses the resistance between two pins, wich are in contact with the fuel. When there is no water in the fuel, the resistance is very high. If there is any water in the fuel, the resistance falls. At a threshold resistance (water has been detected), the switch output signal (yellow cable) to the engine control unit pin B8 will be pulled down to zero.

 

 

MID 128, PID 100 Engine oil pressure

MID 128: Engine control unit

 

FMI 1 – Data valid but below operational range

Fault code explanation:

Oil pressure is too low

Fault indication:

DCU: Engine warning in DCU display

CIU: Flash code

Flash code

Electrical fault: 3.1

Value fault: 6.6

Symptom:

Power is reduced due to error torque map if engine protection parameter is

activated.

Conditions for fault code:

Oil pressure depends on the engine revolution. Oil pressure exceeds the set

value of the engine protection parameter

Possible reason:

• Too low engine oil level.

• Blocked oil filter.

• Oil leakage.

• Faulty oil pressure sensor.

Suitable action:

1 Check engine oil level and quality of the oil.

2 Change engine oil and oil filter to prevent blocked oil filter.

3 Check that no engine oil leakage occurs.

4 Check function of oil pressure sensor by control measuring the engine

oil pressure (see workshop manual Group 21-26).

Measurements:

• Checking oil pressure sensor page 121

 

 

 

FMI 3 – Voltage above normal or short circuit to higher voltage

Fault code explanation:

Faulty sensor / Faulty sensor circuit

Fault indication:

DCU: Engine warning in DCU display

CIU: Flash code

Flash code

Electrical fault: 3.1

Value fault: 6.6

Symptom:

None

Conditions for fault code:

The voltage on pin B11 on the EMS 2 is more than 4.95 Volt.

Possible reason:

• Short circuit between signal cable and 5V supply to oil pressure sensor.

• Faulty sensor.

Suitable action:

1 Check cable harness and connectors between oil pressure sensor and

EMS 2.

2 Check function of oil pressure sensor.

Measurements:

• Checking supply cable, oil pressure sensor page 119

• Checking negative cable, oil pressure sensor page 120

• Checking signal cable, oil pressure sensor page 120

• Checking oil pressure sensor page 121

 

 

FMI 5 – Current below normal or open circuit

Fault code explanation:

Faulty sensor / Faulty sensor circuit

Fault indication:

DCU: Engine warning in DCU display

CIU: Flash code

Flash code

Electrical fault: 3.1

Value fault: 6.6

Symptom:

None

Conditions for fault code:

The voltage on pin B11 on the EMS 2 is less than 0.07 Volt.

Possible reason:

• An open circuit in 5V supply cable to oil pressure sensor.

• An open circuit in signal cable to oil pressure sensor.

• Short circuit between signal cable and battery negative to oil pressure

sensor.

• Faulty sensor.

Suitable action:

1 Check contact pressure in socket 11 and 17 in engine connector B. Also

check contact pressure in connector at oil pressure sensor.

2 Check cable harness and connectors between oil pressure sensor and

EMS 2.

3 Check function of oil pressure sensor.

Measurements:

• Checking supply cable, oil pressure sensor page 119

• Checking negative cable, oil pressure sensor page 120

• Checking signal cable, oil pressure sensor page 120

• Checking oil pressure sensor page 121

 

 

Circuit description

The sensor is an active sensor, i.e. the sensor must receive operating voltage. Pin B17 on the engine control unit (EMS 2) provides pin 1 on the sensor with an operating voltage of +5 Volt. Pin 3 or pin 4 (depended of engine type) on the sensor is connected to battery negative via pin B18 on the EMS 2. The output signal from the pressure sensor, pin 2 on the sensor to pin B11 on the EMS 2, is a voltage signalthat is proportional to the oil pressure (after the oil filters).

 

Component specification

Working range: 0 – 7 bar = 0 – 700 kPa

Supply voltage: 5,00 +/- 0,25 VDC

Nominal output voltage at 25 °C and at supply voltage

5.00 VDC:

0,5 VDC at 0 bar = 0 kPa

4,5 VDC at 7 bar = 700 kPa

 

 

MID 128, PID 105 Intake manifold temperature

MID 128: Engine control unit

 

FMI 0 – Data valid but above normal operational range

Fault code explanation:

Inlet manifold temperature is too high

Fault indication:

DCU: Engine warning in DCU display

CIU: Flash code

Flash code

Electrical fault: 3.2

Value fault: 6.2

Symptom:

Engine is derated if engine protection parameter is activated.

Conditions for fault code:

Inlet manifold temperature exceeds the set value of the engine protection

parameter.

Possible reason:

• Engine temperature is too high.

• High surrounding temperature.

• Dust or dirt on the outside of the intercooler.

• Faulty inlet manifold temperature sensor.

Suitable action:

1 Check that engine temperature is normal.

2 Clean the intercooler.

3 Check function of inlet manifold temperature sensor.

Measurements:

• Checking inlet manifold temperature sensor page 124

 

 

 

FMI 4 – Voltage below normal or short circuit to lower voltage

Fault code explanation:

Faulty sensor / Faulty sensor circuit

Fault indication:

DCU: Engine warning in DCU display

CIU: Flash code

Flash code

Electrical fault: 3.2

Value fault: 6.2

Symptom:

Temperature is set to 40° C

Conditions for fault code:

The voltage on pin B47 on the EMS 2 is less than 0.07 Volt.

Possible reason:

• Short circuited sensor signal cable to battery negative.

• Faulty sensor.

Suitable action:

1 Check cable harness and connectors between inlet manifold temperature

sensor and EMS 2.

2 Check function of inlet manifold temperature sensor.

Measurements:

• Checking signal cable, inlet manifold temperature sensor page 121

• Checking negative cable, inlet manifold pressure/temperature

sensor page 122

• Checking sensor cable, inlet manifold temperature sensor page 123

• Checking inlet manifold temperature sensor page 124

 

 

For More Volvo Engine workshop information, please visit

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