FUSO 4M4 – FUEL AND ENGINE CONTROL – INSPECTION OF ELECTRICAL EQUIPMENT

#001 Inspection of combination switch
AK14A connector connection table

• For other inspections than shown above, see Gr54.
• If there is any abnormality, replace the switch. (See Gr37.)

#002 Inspection of starter switch
AP2A, AN6A connector connection table

• Terminal numbers within parentheses ( ) show terminals of AP2A.
• If any fault is found, replace the switch. (See Gr37.)

#157 Inspection of idling speed adjustment potentiometer
• Apply 5 volts DC to terminals 1 and 2 of the idling speed adjustment potentiometer.
• Turn the knob fully counterclockwise. Then, measure the output voltage across terminals 2 and 3 (see the diagrams on the left) while slowly turning the knob clockwise.
• If any measurement is out of specification, replace the idling speed adjustment potentiometer.

#201 Inspection of relay (normally open type 5 pin)
• Perform continuity check and operation check, and if any fault is found, replace the relay.

#262 Inspection of water temperature sensor
• Place the water temperature sensor in a container filled with engine oil.
• Heat the oil to each of the specified temperatures. Stir the oil well while doing so.
• Measure the resistance between terminals 1 and 2.

• If either measurement is out of specification, replace the sensor.

#263 Inspection of engine speed sensor
• Measure the resistance between terminals 1 and 2.

• If the measurement is out of specification, replace the sensor.

#265 Inspection of vehicle speed sensor
• With the 24 volts DC applied to terminals to 1 and 2, slowly turn the shaft of the vehicle speed sensor.
• Measure the maximum voltage (high pulse voltage) and minimum voltage (low pulse voltage) occurring at each specified pair of terminals.

• If any measurement is out of specification, replace the sensor.

#305 Inspection of intake air temperature sensor 1
• Place the sensor in a container filled with engine oil.
• Heat the oil to each of the specified temperatures. Stir the oil well while doing so.
• Measure the resistance between terminals 1 and 2.

• If either measurement is out of specification, replace the sensor.

#317 Inspection of power take-off load sensor
• Apply 5 volts DC to terminals 4 and 6.
• Measure the output voltage across terminals 5 and 6 with the lever at idling position A and at full-load position B.

• If measurement of full-load position B deviates from standard value, adjust with full load stopper bolt.
• If measurement of idling position A deviates from standard value, replace the sensor.

#318 Inspection of boost pressure sensor
• Apply 5 volts DC to terminals 3 and 1.
• Apply air pressure. Gradually increase it and, while doing so, measure the output voltage occurring at terminals 2 and 1.

• If any measurement is out of specification, replace the sensor.

#319 Inspection of common rail pressure sensor
• The sensor cannot easily be inspected in isolation, so you must evaluate it indirectly by inspection of system harnesses and related parts.
• If there is no abnormality in any related part but the system is abnormal, replace the common rail.

#320 Inspection of cylinder recognition sensor
• Measure the resistance between terminals 2 and 3.

• If the measurement is out of specification, replace the sensor.

#565 Inspection of exhaust shutter 3-way magnetic valve
• Perform the following checks. If there is any abnormality, replace the exhaust shutter 3-way magnetic valve.
(1) Check of operation
• Gradually increase from zero the voltage applied to terminals 1 and 2.
• Observe the voltage when the exhaust shutter 3-way magnetic valve operates.
(Determine the magnet valve’s OFF-ON operation from the operating sound.)

(2) Inspection of air circuit for continuity, air-tightness and reducing valve activation
• Pipe the air circuit as shown, and check that when a negative pressure of 93 kPa {700 mmHg} is applied to the IN port to activate M/V1, the vacuum gauge reads 93 kPa {700 mmHg}. Also, check that atmospheric pressure is not let in from the EXH side port.
• Check that when M/V2 is activated with a negative pressure of 93 kPa {700 mmHg} applied to the IN port, the vacuum gauge reading is within the specified limit.

#574 Inspection of MPROP
(rail pressure control valve)
• Measure the resistance between terminals 1 and 2.

• If the measurement is out of specification, replace the supply pump.

#582 Inspection of injector magnetic valve
• Measure the resistance between terminals 1 and 2.

#828 Inspection of fuel injection rate adjustment resistor, power take-off resistor and controller area network resistor
• Measure the resistance of the resistor number marked on the fuel injection rate adjustment resistor, power take-off resistor and controller area network resistor.

• If the measurement is out of specification, replace the fuel injection rate adjustment resistor, power take-off resistor and controller area network resistor with one that has the same resistor number and same specified resistance.

 

 

 

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