ENGINE (DIAGNOSTICS)(H4DOTC DIESEL) > Diagnostic Procedure with Diagnostic Trouble Code (DTC)

DTC P1234 FUEL PRESSURE ABNORMAL (FUEL PUMP FAILURE 2)

DTC DETECTING CONDITION:

Immediately at fault recognition

TROUBLE SYMPTOM:

Engine stalls.

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode and Inspection Mode .

WIRING DIAGRAM:

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1.CHECK FOR ANY OTHER DTC ON DISPLAY.

Are DTCs other than P1233 and P1234 displayed?

Check the appropriate DTC using the “List of Diagnostic Trouble Code (DTC)”.

2.CHECK SUCTION CONTROL VALVE.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from the suction control valve.

3) Measure the resistance between suction control valve terminals.

NOTE:

Measure the resistance when suction control valve temperature is 20°C (68°F).

Terminals

No. 1 — No. 2:

Is the resistance 1.8 — 2.4 Ω?

Replace the suction control valve.

3.CHECK COMMON RAIL PRESSURE SENSOR.

1) Disconnect the connector from the common rail pressure sensor.

2) Measure the resistance between common rail pressure sensor terminals.

Terminals

No. 1 — No. 2:

No. 2 — No. 3:

Is the resistance No. 1 — No. 2: approx. 13.7 kΩ and No. 2 — No. 3: approx. 2.5 kΩ?

Replace the common rail assembly.

4.CHECK FUEL DELIVERY LINE (LOW PRESSURE LINE).

Check for damage in fuel delivery line (low pressure line), leaks at connection, and air entering into line.

NOTE:

To check for air in the system, replace the fuel hose between the fuel filter assembly to the fuel pump with an appropriate size clear oil proof/heat proof hose, and check the condition of the fuel when the engine is idled. After completing the check, make sure to restore the original fuel hose, and fill the fuel system by operating the priming pump.

Is there damage in fuel delivery line (low pressure line), leaks at connection, and air entering into line?

Identify the faulty parts, and repair.

NOTE:

In this case, repair the following item:

• Air entering by fuel running out: start the engine to bleed the air completely.

• Other than air entering by fuel running out: replace the faulty part.

5.CHECK FUEL DELIVERY LINE (HIGH PRESSURE LINE).

Check fuel delivery line (high pressure line) using Subaru Select Monitor.

WARNING:

When checking fuel delivery line during engine operation, be very careful so that one's hair, body and clothes do not touch the rotating part in the engine compartment.

NOTE:

For detailed procedures, refer to “High Pressure Fuel Inspection”.

Are there leaks from the fuel delivery line (high pressure line)?

Replace the faulty fuel delivery line.

Repair the fuel leaks into engine internal.

NOTE:

In this case, repair the following item:

• Fuel injector

• Fuel delivery pipe (fuel injector)