EN(H6DO)-102
ENGINE (DIAGNOSTICS)
DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
Value
Yes
No
1
CHECK GROUND CIRCUIT OF ECM.
Measure resistance of harness between ECM
connector and chassis ground.
Connector & terminal
(B137) No. 31 — Chassis ground:
(B137) No. 21 — Chassis ground:
(B137) No. 8 — Chassis ground:
(B137) No. 9 — Chassis ground:
Is the measured value less than the specified
value?
5
Ω
Go to step 2.
Repair harness
and connector.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
ECM and engine
ground terminal
• Poor contact in
ECM connector
Poor contact in
coupling connector
2
CHECK CURRENT DATA.
1) Start engine
2) Read data of front oxygen (A/F) sensor
heater current using Subaru Select Monitor
or OBD-II general scan tool.
Does the measured value exceed the spec-
ified value?
NOTE:
• Subaru Select Monitor
For detailed operation procedure, refer to the
“READ CURRENT DATA FOR ENGINE”.
<Ref. to EN(H6DO)-34, Subaru Select Moni-
tor.>
• OBD-II scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Instruction Manual.
0.2 A
Repair poor con-
tact in connector.
NOTE:
In this case, repair
the following:
• Poor contact in
front oxygen (A/F)
sensor connector
• Poor contact in
ECM connector
Go to step 3.
3
CHECK OUTPUT SIGNAL FROM ECM.
1) Start and idle the engine.
2) Measure voltage between ECM connector
and chassis ground.
Connector & terminal
(B137) No. 4 (+) — Chassis ground (
−−−−
):
Is the measured value less than the speci-
fied value?
1.0 V
Go to step 5.
Go to step 4.
4
CHECK OUTPUT SIGNAL FROM ECM.
Measure voltage between ECM connector and
chassis ground.
Connector & terminal
(B137) No. 4 (+) — Chassis ground (
−−−−
):
Does the voltage change less than the speci-
fied value by shaking harness and connector
of ECM while monitoring the value with voltage
meter?
1.0 V
Repair poor con-
tact in ECM con-
nector.
Go to step 5.
5
CHECK OUTPUT SIGNAL FROM ECM.
Measure voltage between ECM connector and
chassis ground.
Connector & terminal
(B137) No. 5 (+) — Chassis ground (
−−−−
):
Is the measured value less than the specified
value?
1.0 V
Go to step 7.
Go to step 6.