1.CHECK CURRENT DATA.
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”. 
• General scan tool
For detailed operation procedures, refer to the general scan tool operation manual.
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Is the measured value less than 13.3 kPa (100 mmHg, 3.94 inHg) ?
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Even if DTC is detected, the circuit has returned to a normal condition at this time. Reproduce the fault condition, and reperform the check.
NOTE:
In this case, there may be a temporary connector contact failure.
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2.CHECK POWER SUPPLY OF THE MANIFOLD 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 (−):
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Is the voltage 4.5 V or more?
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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
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3.CHECK HARNESS BETWEEN ECM AND MANIFOLD ABSOLUTE PRESSURE SENSOR 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:
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Is the resistance less than 1 Ω?
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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
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4.CHECK HARNESS BETWEEN ECM AND MANIFOLD ABSOLUTE PRESSURE SENSOR CONNECTOR.
Measure the resistance between ECM and chassis ground.
Connector & terminal
(B134) No. 6 — Chassis ground:
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Is the resistance 1 MΩ or more?
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Repair ground short circuit of harness between ECM and manifold absolute pressure sensor connector.
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5.CHECK FOR POOR CONTACT.
Check for poor contact between the ECM and manifold pressure sensor connector.
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Is there poor contact in the ECM or manifold absolute pressure sensor connector?
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Repair the poor contact in the ECM or manifold absolute pressure sensor connector.
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Replace the manifold absolute pressure sensor. 
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