Subaru IMPREZA GD 2007 Series Manual page 192

asieps_tobira_IM_US.book 83 ページ ２０１２年１月１７日 火曜日 午後３時４８分
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
1 CHECK HARNESS BETWEEN ECM AND
FRONT OXYGEN (A/F) SENSOR CONNEC-
TOR.
1) Start and warm-up the engine.
2) Turn the ignition switch to OFF.
3) Disconnect the connectors from the ECM
and front oxygen (A/F) sensor.
4) Measure the resistance of harness between
ECM and front oxygen (A/F) sensor connector.
Connector & terminal
(B136) No. 2 — (E118) No. 4:
(B136) No. 3 — (E118) No. 4:
2 CHECK HARNESS BETWEEN ECM AND
FRONT OXYGEN (A/F) SENSOR CONNEC-
TOR.
Measure the resistance of harness between
ECM and front oxygen (A/F) sensor connector.
Connector & terminal
(B135) No. 9 — (E118) No. 1:
(B135) No. 8 — (E118) No. 3:
3 CHECK FRONT OXYGEN (A/F) SENSOR.
Measure the resistance between front oxygen
(A/F) sensor connector terminals.
Terminals
No. 6 — No. 4:
4 CHECK POOR CONTACT.
Check poor contact of ECM and front oxygen
(A/F) sensor connector.
Check
Is the resistance less than 1 Ω? Go to step 2.
Is the resistance less than 1 Ω? Go to step 3.
Is the resistance less than 5 Ω? Go to step 4.
Is there poor contact in ECM or
front oxygen (A/F) sensor con-
nector?
EN(H4SO)(diag)-83
ENGINE (DIAGNOSTICS)
Yes No
Repair the open
circuit of harness
between ECM and
front oxygen (A/F)
sensor connector.
Repair the open
circuit of harness
between ECM and
front oxygen (A/F)
sensor connector.
Replace the front
oxygen (A/F) sen-
sor. <Ref. to
FU(H4SO)-36,
Front Oxygen (A/F)
Sensor.>
Repair the poor Replace the front
contact of ECM or oxygen (A/F) sen-
front oxygen (A/F) sor. <Ref. to
sensor connector. FU(H4SO)-36,
Front Oxygen (A/F)
Sensor.>