Subaru IMPREZA GD 2007 Series Manual page 1650

asieps_tobira_IM_US.book 319 ページ ２０１２年１月１７日 火曜日 午後３時４８分
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
7 CHECK OUTPUT SIGNAL FOR ECM.
Measure the voltage between front oxygen (A/F)
sensor connector and chassis ground.
Connector & terminal
(B18) No. 4 (+) — Chassis ground (–):
(B18) No. 3 (+) — Chassis ground (–):
8 CHECK EXHAUST SYSTEM.
9 CHECK AIR INTAKE SYSTEM.
10 CHECK FUEL PRESSURE.
WARNING:
Place "NO OPEN FLAMES" signs near the
working area.
CAUTION:
Be careful not to spill fuel.
1) Connect the front oxygen (A/F) sensor con-
nector.
2) Measure the fuel pressure while discon-
necting pressure regulator vacuum hose from
intake manifold. <Ref. to ME(H4DOTC)-31,
INSPECTION, Fuel Pressure.>
CAUTION:
Release fuel pressure before removing the
fuel pressure gauge.
NOTE:
If fuel pressure does not increase, squeeze the
fuel return hose 2 or 3 times, then measure fuel
pressure again.
11 CHECK FUEL PRESSURE.
After connecting the pressure regulator vacuum
hose, measure fuel pressure. <Ref. to
ME(H4DOTC)-31, INSPECTION, Fuel Pres-
sure.>
CAUTION:
Release fuel pressure before removing the
fuel pressure gauge.
NOTE:
• If fuel pressure does not increase, squeeze
fuel return hose 2 or 3 times, then measure fuel
pressure again.
• If the measured value at this step is out of
specification, check or replace pressure regula-
tor and pressure regulator vacuum hose.
Check
Is the voltage 8 V or more?
Are there holes or loose bolts
on exhaust system?
Are there holes, loose bolts or
disconnection of hose on air
intake system?
Is the measured value 284 —
314 kPa (2.9 — 3.2 kgf/cm
— 46 psi)?
Is the measured value 230 —
260 kPa (2.35 — 2.65 kgf/cm
33 — 38 psi)?
EN(STI)(diag)-319
ENGINE (DIAGNOSTICS)
Yes
Repair the short Repair poor con-
circuit to power in tact of the ECM
the harness connector.
between the ECM
and front oxygen
(A/F) sensor con-
nector. After repair,
replace the ECM.
<Ref. to
FU(H4DOTC)-50,
Engine Control
Module (ECM).>
Repair the exhaust Go to step 9.
system.
Repair the air Go to step 10.
intake system.
Go to step 11.
Repair the follow-
2
, 41 ing item.
Fuel pressure is
too high:
• Clogged fuel
return line or bent
hose
Fuel pressure is
too low:
• Improper fuel
pump discharge
• Clogged fuel
supply line
Go to step 12.
Repair the follow-
2
, ing item.
Fuel pressure is
too high:
• Faulty pressure
regulator
• Clogged fuel
return line or bent
hose
Fuel pressure is
too low:
• Faulty pressure
regulator
• Improper fuel
pump discharge
• Clogged fuel
supply line
No