Subaru LEGACY 2006 Manual page 149

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Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
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 procedure, refer to
"READ CURRENT DATA FOR ENGINE". <Ref.
to EN(H4SO)(diag)-26, Subaru Select Moni-
tor.>
• General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.
2 CHECK OUTPUT SIGNAL OF ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B134) No. 19 (+) — Chassis ground (–):
3 CHECK OUTPUT SIGNAL OF ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B134) No. 19 (+) — Chassis ground (–):
4 CHECK INPUT SIGNAL OF ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B134) No. 6 (+) — Chassis ground (–):
5 CHECK INPUT SIGNAL FOR ECM (USING
SUBARU SELECT MONITOR).
Read the data of atmospheric absolute pres-
sure signal using Subaru Select Monitor.
NOTE:
Subaru Select Monitor
For detailed operation procedure, refer to
"READ CURRENT DATA FOR ENGINE". <Ref.
to EN(H4SO)(diag)-26, Subaru Select Moni-
tor.>
6 CHECK HARNESS BETWEEN ECM AND
MANIFOLD ABSOLUTE PRESSURE SEN-
SOR CONNECTOR.
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 (–):
Check
Is the measured value more
than 119.5 kPa (896.5 mmHg,
35.29 inHg) ?
Is the voltage more than 4.5 V? Go to step 4.
Does the voltage change by
shaking the ECM harness and
connector?
Is the voltage less than 0.2 V? Go to step 6.
Is the measured value more
than 13.3 kPa (100 mmHg,
3.94 inHg) when shaking the
ECM harness and connector?
Is the voltage more than 4.5 V? Go to step 7.
EN(H4SO)(diag)-112
Yes No
Go to step 10. Go to step 2.
Go to step 3.
Repair the poor Contact the SOA
contact of ECM service center.
connector.
Go to step 5.
Repair the poor Go to step 6.
contact of ECM
connector.
Repair the open
circuit of harness
between ECM and
manifold absolute
pressure sensor
connector.