Flow meter power supply check

Detach the connector attached to the flow meter -Insert disconnector AD 456 n° 1806590000 across the flow meter connector and the wiring connector

Connect the positive probe of an Examiner to pin 1 and the negative probe to earth.

Turn the ignition key to the MAR position and check that the battery voltage is more than 11 Volts.

Move on to Step 2

Restore the continuity or, if necessary, replace the electrical wiring between the engine control unit and the flow meter

See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT

Replace the junction unit

Op. 5505A13

Flow meter earth check

Connect the Examiner test probes across pins 1 and 2 of the disconnector

Check the voltage is greater than 11 V.

Move on to Step 3

Repair or, if necessary, replace the electrical wiring between the engine management control unit and the flow meter

See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT

Replace the engine management control unit

Op. 1060G80 DIESEL ELECTRONIC INJECTION CONTROL UNIT - R.R

Air flow rate signal check

Connect the Examiner in voltmeter mode across pins 4 and 2 of the disconnector

Select the following full scale deflection values on the Voltmeter: Voltage 20 Volts f.s.d

Time base: 2 secs

Press START

With the engine idling, check for the presence of an air flow signal as shown in the attached graph.

The signal pattern is subordinate to the quantity of air coming into the flow meter. If the air flow is increased, the voltage amplitude does not change significantly but the frequency of the output signal increases

Repair or, if necessary, replace the electrical wiring between the engine management control unit and the flow meter

See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT

Check the seal of the flow meter hose, replace the flow meter if it is OK.

Op. 1060G10 AIR FLOW METER - R.R.

Aspirated air temperature signal check

Connect the Examiner in voltmeter mode across pins 3 and 2 of the disconnector

With the engine idling

Press the START button on the voltmeter

Check for the presence of an air temperature square-wave signal with a working voltage of 5V and a duty cycle oscillating between 10% (with min. air temperature) and 90% (with max. air temperature), as in the attached graph.

Replace the flow meter

Op. 1060G10 AIR FLOW METER - R.R.