Description

First of all check damage of harness and terminals : Check terminals for contact resistance, corrosion and deformation.

When hard starting occurs after parking for a long time in the winter (blow -5℃), Inspect diesel fuel whether it is frozen or not and fuel filter heater.

Diagnostic Procedure
Fuel filter heater relay inspection
1.

IG KEY "OFF", ENGINE "OFF"

2.

Remove the fuel filter heater relay.

3.

Measure the voltage of the fuel filter relay terminal.

Symptom

Inspection procedure

Case1

● Battery voltage is not supplied at terminal "1".

● Repair fusible link blown. (Fusible link supplies battery power to "1" terminal.)

● If the fusible link is blown again, repair short to ground in fuel filter heater relay power circuit.

Case2

● Battery voltage is not supplied at terminal "2".

● Repair fusible link blown. (Fusible link supplies battery power to "2" terminal.)

● If the fusible link is blown again, repair short to ground in fuel filter heater relay power circuit.

Fuel filter heater switch(Thermo swith) circuit inspection
4.

IG KEY "OFF", ENGINE "OFF"

5.

Disconnect the fuel filter heater switch(Thermo switch) connector.

6.

IG KEY "ON", ENGINE "OFF"

7.

Measure the voltage of the fuel filter heater switch (Thermo switch) connector. (Fuel filter relay is installed.)

Symptom

Inspection procedure

Case1

● Battery voltage is not supplied at terminal "2".

● Repair open in fuel filter heater relay control circuit.

● If there is no problem in fuel filter heater relay control circuit, Go to "Fuel filter heater relay inspection"

8.

Inspect fuel filter heater switch ground circuit.

■ Specification : Below 1.0 Ω (20℃)

9.

Connect fuel filter heater switch(Thermo switch) connector terminal "1" and "2" directly with jump wire.

Symptom

Inspection procedure

Case1

● Fuel filter relay is actuated and fuel filter is hot after approx 20 seconds.

● Inspect the fuel filter heater switch (Thermo switch).

● Fuel filter heater switch should be actuated (continuity) in the below -5℃ (Using a refrigerator)

Case2

● Fuel filter relay is actuated but fuel filter is not hot.

● Go to "fuel filter heater power circuit inspection" as below.

Case3

● Fuel filter relay is not actuated.

● Go to "fuel filter relay inspection"

Fuel filter heater power circuit inspection
10.

IG KEY "OFF", ENGINE "OFF"

11.

Remove the fuel filter heater relay.

12.

Before measuring resistance, you must calibrate(0Ω) the tester.

note

Refer to "Multimeter calibration inspection" of detail inspections (Equipment settings).

13.

Measure the resistance between fuel filter heater relay terminal "5" and chassis ground.

■ Specification : 0.5Ω ± 10% ( 20℃ )

Symptom

Inspection procedure

Case1

● There is discontinuity between fuel filter heater relay terminal "5" and chassis ground.

● Go to "Fuel filter heater inspection" and inspect fuel filter heater resistance.

● If fuel filter heater resistance is normal, repair open in fuel filter heater power (ground) circuit.

Яндекс.Метрика