Subaru Legacy 2005 Service Manual page 1898

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
6 CHECK HARNESS BETWEEN EGR SOLE-
NOID VALVE AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Detach the connector from EGR solenoid
valve and ECM.
3) Measure the resistance of harness
between EGR solenoid valve and ECM con-
nector.
Connector & terminal
(B134) No. 8 — (E18) No. 6:
(B134) No. 10 — (E18) No. 1:
(B134) No. 9 — (E18) No. 4:
(B134) No. 11 — (E18) No. 3:
7 CHECK HARNESS BETWEEN EGR SOLE-
NOID VALVE AND ECM CONNECTOR.
Measure the resistance of harness between
EGR solenoid valve and chassis ground.
Connector & terminal
(B134) No. 8 — Chassis ground:
(B134) No. 9 — Chassis ground:
(B134) No. 10 — Chassis ground:
(B134) No. 11 — Chassis ground:
8 CHECK POOR CONTACT.
Check poor contact in ECM and EGR solenoid
valve connector.
BN:DTC P0420 CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD
(BANK1)
DTC DETECTING CONDITION:
Detects when malfunction occurs in 2 continuous driving cycles.
TROUBLE SYMPTOM:
• Engine stalls.
• Idle mixture is out of specifications.
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H6DO)(diag)-41,
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H6DO)(diag)-34, PROCEDURE,
Inspection Mode.>.
Check
Is the resistance less than 1
Ω?
Is the resistance more than 1
MΩ?
Is there poor contact in ECM or
EGR solenoid valve connec-
tor?
EN(H6DO)(diag)-202
Yes
Go to step 7. Repair the open
circuit of harness
between ECM and
EGR solenoid
valve connector.
Go to step 8. Repair the short
circuit of harness
between main
relay and EGR
solenoid valve
connector.
Repair the poor Even if the mal-
contact in ECM function indicator
and EGR solenoid light illuminates,
valve connector. the circuit has
returned to a nor-
mal condition at
this time.
No