GDI ± Troubleshooting
13A-29
Code No.56 Abnormal fuel pressure Probable cause
Range of check
D Ignition switch: ON
Set conditions
D Sensor output voltage is 4.8 V or more for four seconds.
or
D Sensor output voltage is 0.2 V or less for four seconds.
Range of check
D After the engine is started, the following condition has been detected:
(1) Engine speed: 1,000 r/min or more
(2) Fuel pressure: 2 MPa or more
D While engine is running
Set conditions
D Fuel pressure is 6.9 MPa or more for four seconds.
or
D Fuel pressure is 2 MPa or less for four seconds.
D Malfunction of the fuel pressure sensor
D Open circuit or short-circuited harness wire of the
fuel pressure sensor
D Malfunction of the engine-ECU
D Malfunction of the fuel pump (high pressure)
D Malfunction of the fuel pressure regulator (high
pressure)
D Clogged high-pressure fuel line
This diagnosis code is also output when air is sucked in high-pressure fuel line
due to no fuel supply.
In this case, air can be bled by letting the engine run at 2,000 r/min for at
least fifteen seconds. After the air bleeding, the diagnosis code must be erased
by the MUT-II.
D Air sucking due to no fuel supply
OK
NG
D Replace the fuel pump (high
pressure) (poor pump discharge
pressure)
D Replace the high-pressure regula-
tor (fuel leakage at the return side).
Check trouble symptom.
NG
Check if input voltage from the fuel
pressure sensor to engine-ECU
changes suddenly by performing an
intermittent malfunction simulation test.
(Refer to GROUP 00 ± Points to Note
for Intermittent Malfunction.)
OK
Normal
NG
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MUT-II Data list
74 Fuel pressure sensor
(Refer to P.13A-75.)
D Ignition switch: ON
OK: 0 ± 8 MPa
OK
MUT-II Data list
74 Fuel pressure sensor
(Refer to P.13A-75.)
D Maintain the engine speed at 2,000
r/min for at least fifteen seconds.
OK: 6.9 MPa or less
NG
D Replace the high-pressure fuel
regulator (seized regulator).
D Replace the high-pressure return
pipe (seized pipe).
MUT-II Data list
74 Fuel pressure sensor
(Refer to P.13A-75.)
D Engine: Idle running for at least
three minutes
OK: 4 MPa or more
OK
Erase diagnosis code No.56. (This
diagnosis code has been output due
to air sucking into high-pressure fuel
line. But that problem has been re-
solved by revving the engine at 2,000
r/min.)
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