Subaru 2009 IMPREZA Service Manual page 679

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
1 CHECK POWER SUPPLY TO EGR VALVE.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from EGR valve.
3) Turn the ignition switch to ON.
4) Measure the voltage between EGR valve
connector and engine ground.
Connector & terminal
(E18) No. 2 (+) — Engine ground (–):
(E18) No. 5 (+) — Engine ground (–):
2 CHECK HARNESS BETWEEN ECM AND
EGR VALVE CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM.
3) Measure the resistance between ECM and
EGR valve connector.
Connector & terminal
DTC P1492; (B134) No. 8 — (E18) No. 3:
DTC P1494; (B134) No. 9 — (E18) No. 1:
DTC P1496; (B134) No. 10 — (E18) No. 4:
DTC P1498; (B134) No. 20 — (E18) No. 6:
3 CHECK HARNESS BETWEEN ECM AND
EGR VALVE CONNECTOR.
1) Disconnect the connectors from ECM.
2) Measure the resistance between ECM and
chassis ground.
Connector & terminal
DTC P1492; (B134) No. 8 — Chassis
ground:
DTC P1494; (B134) No. 9 — Chassis
ground:
DTC P1496; (B134) No. 10 — Chassis
ground:
DTC P1498; (B134) No. 20 — Chassis
ground:
4 CHECK POOR CONTACT.
Check poor contact of ECM and EGR valve
connector.
Check
Is the voltage 10 V or more?
Is the resistance less than 1 ? Go to step 3.
Is the resistance 1 M or
more?
Is there poor contact of ECM or
EGR valve connector?
EN(H4SO)(diag)-262
Yes No
Go to step 2. Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
EGR valve
main relay connec-
tor
• Poor contact of
coupling connector
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
ECM and
valve connector
• Poor contact of
coupling connector
Go to step 4. Repair the ground
short in harness
between ECM and
EGR valve con-
nector.
Repair the poor Replace the EGR
contact of ECM or valve. <Ref. to
EGR valve con- FU(H4SO)-35,
nector. EGR Valve.>
and
EGR