Subaru Legacy 2005 Service Manual page 1863

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
7 CHECK FUEL PRESSURE.
After connecting the pressure regulator vac-
uum hose, measure fuel pressure.
Warning:
Release fuel pressure before removing the
fuel pressure gauge.
NOTE:
• If fuel pressure does not increase, squeeze
fuel return hose 2 to 3 times, then measure
fuel pressure again.
• If the measured value at this step is out of
specifications, check or replace pressure regu-
lator and pressure regulator vacuum hose.
8 CHECK ENGINE COOLANT TEMPERATURE
SENSOR.
1) Start the engine and warm-up completely.
2) Read the data of engine coolant tempera-
ture sensor signal using Subaru Select Monitor
or general scan tool.
NOTE:
• Subaru Select Monitor
For detailed operation procedure, refer to
"READ CURRENT DATA FOR ENGINE". <Ref.
to EN(H6DO)(diag)-26, Subaru Select Moni-
tor.>
• General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
9 CHECK MANIFOLD PRESSURE SENSOR
SIGNAL.
1) Start and warm-up the engine until engine
coolant temperature is above 60°C (140°F).
2) Place the select lever in "N" or "P" position.
3) Turn the A/C switch to OFF.
4) Turn all the accessory switches to OFF.
5) Read the data of manifold absolute pres-
sure sensor signal using Subaru Select Moni-
tor or general scan tool.
NOTE:
• Subaru Select Monitor
For detailed operation procedure, refer to
"READ CURRENT DATA FOR ENGINE". <Ref.
to EN(H6DO)(diag)-26, Subaru Select Moni-
tor.>
• General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
Check
Is fuel pressure 279 — 309
kPa (2.85 — 3.15 kgf/cm
— 45 psi)?
Is the engine coolant tempera-
ture 70 — 100°C (158 —
212°F)?
Is the measurement value 24.0
— 41.3 kPa (180 — 310
mmHg, 7.09 — 12.20 inHg)
when idling and 73.3 — 106.6
kPa (550 — 800 mmHg, 21.65
— 31.50 inHg) when the igni-
tion turns to ON?
EN(H6DO)(diag)-167
ENGINE (DIAGNOSTICS)
Yes
Go to step 8. Repair the follow-
ing items.
2
, 40
Fuel pressure is
too high:
Fuel pressure is
too low:
Go to step 9. Replace the
engine coolant
temperature sen-
sor. <Ref. to
FU(H6DO)-18,
Engine Coolant
Temperature Sen-
sor.>
Replace the ECM. Replace the mani-
<Ref. to fold absolute pres-
FU(H6DO)-34, sure sensor. <Ref.
Engine Control to FU(H6DO)-23,
Module (ECM).> Manifold Absolute
Pressure Sensor.>
No
• Faulty pres-
sure regulator
• Clogged fuel
return line or
bent hose
• Faulty pres-
sure regulator
• Improper fuel
pump discharge
• Clogged fuel
supply line