Subaru IMPREZA GD 2007 Series Manual page 218

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Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
1 CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of intake manifold absolute
pressure signal using Subaru Select Monitor or
general scan tool.
NOTE:
• Subaru Select Monitor
For detailed operation procedures, refer to
"READ CURRENT DATA FOR ENGINE". <Ref.
to EN(H4SO)(diag)-32, Subaru Select Monitor.>
• General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
2 CHECK POWER SUPPLY OF THE MANI-
FOLD ABSOLUTE PRESSURE SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from manifold
absolute pressure sensor.
3) Turn the ignition switch to ON.
4) Measure the voltage between manifold
absolute pressure sensor connector and
engine ground.
Connector & terminal
(E21) No. 3 (+) — Engine ground (–):
3 CHECK HARNESS BETWEEN ECM AND
MANIFOLD ABSOLUTE PRESSURE SEN-
SOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from the ECM.
3) Measure the resistance of harness between
ECM and manifold absolute pressure sensor
connector.
Connector & terminal
(B134) No. 6 — (E21) No. 1:
4 CHECK HARNESS BETWEEN ECM AND
MANIFOLD ABSOLUTE PRESSURE SEN-
SOR CONNECTOR.
Measure the resistance between ECM and
chassis ground.
Connector & terminal
(B134) No. 6 — Chassis ground:
5 CHECK POOR CONTACT.
Check for poor contact between the ECM and
manifold pressure sensor connector.
Check
Is the measured value less than
13.3 kPa (100 mmHg, 3.94
inHg) ?
Is the voltage 4.5 V or more?
Is the resistance less than 1 Ω? Go to step 4.
Is the resistance 1 MΩ or
more?
Is there poor contact in the
ECM or manifold absolute pres-
sure sensor connector?
EN(H4SO)(diag)-109
ENGINE (DIAGNOSTICS)
Yes No
Go to step 2. Even if the malfunc-
tion indicator light
illuminates, the cir-
cuit has returned to
a normal condition
at this time. Repro-
duce the fault con-
dition, and
reperform the
check.
NOTE:
In this case, there
may be a tempo-
rary connector
contact failure.
Go to step 3. Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit of
harness between
ECM and manifold
absolute pressure
sensor connector.
• Poor contact in
ECM connector
• Poor contact of
coupling connector
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit of
harness between
ECM and manifold
absolute pressure
sensor connector.
• Poor contact of
coupling connector
Go to step 5.
Repair short cir-
cuit of the harness
to ground between
ECM and manifold
absolute pressure
sensor connector.
Repair the poor Replace the mani-
contact in the ECM fold absolute pres-
or manifold abso- sure sensor. <Ref.
lute pressure sen- to FU(H4SO)-27,
sor connector. Manifold Absolute
Pressure Sensor.>