Subaru IMPREZA 2004 Service Manual page 407

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
7 CHECK HARNESS BETWEEN MANIFOLD
ABSOLUTE PRESSURE SENSOR AND ECM
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 abso-
lute pressure sensor connector and engine
ground.
Connector & terminal
(E21) No. 3 (+) — Engine ground ( − − − − ):
8 CHECK HARNESS BETWEEN MANIFOLD
ABSOLUTE PRESSURE SENSOR AND ECM
CONNECTOR.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from ECM.
3)Measure the resistance of harness between
ECM and manifold absolute pressure sensor
connector.
Connector & terminal
(B135) No. 19 — (E21) No. 1:
9 CHECK POOR CONTACT.
Check poor contact in manifold absolute pres-
sure sensor connector.
Check
Is the voltage more than 4.5 V? Go to step 8.
Is the resistance less than 1
Ω?
Is there poor contact in mani-
fold absolute pressure sensor
connector?
EN(H4SO)(diag)-98
Yes
Repair open circuit
in harness
between ECM and
manifold absolute
pressure sensor
connector.
Go to step 9. Repair open circuit
in harness
between ECM and
manifold absolute
pressure sensor
connector.
Repair poor con- Replace the mani-
tact in manifold fold absolute pres-
absolute pressure sure sensor. <Ref.
sensor connector. to FU(H4SO)-33,
Manifold Absolute
Pressure Sensor.>
No