EN(H4DOTC)(diag)-440
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
Check
Yes
No
1
CHECK CURRENT DATA.
1) Turn the ignition switch to ON.
2) Read the value of «Sec. Air Piping Pres-
sure» using Subaru Select Monitor.
NOTE:
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H4DOTC)(diag)-40, Subaru Select Moni-
tor.>
Is the value of «Sec. Air Piping
Pressure» less than 53.3 kPa
(400 mmHg, 15.8 inHg)?
Go to step
2.
Even if DTC is
detected, the cir-
cuit has returned to
a normal condition
at this time. Repro-
duce the failure,
and then perform
the diagnosis
again.
NOTE:
In this case, tem-
porary poor con-
tact of connector,
temporary open or
short circuit of har-
ness may be the
cause.
2
CHECK POWER SUPPLY OF SECONDARY
AIR COMBINATION VALVE.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from secondary
air combination valve RH (models without SI-
DRIVE) or LH (models with SI-DRIVE).
3) Turn the ignition switch to ON.
4) Measure the voltage between the second-
ary air combination valve RH or LH connector
and chassis ground.
Connector & terminal
Models without SI-DRIVE
(E41) No. 1 (+) — Chassis ground (–):
Models with SI-DRIVE
(E40) No. 1 (+) — Chassis ground (–):
Is the voltage 4.5 V or more?
Go to step
3.
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
ECM
connector
and secondary air
combination valve
RH or LH connec-
tor
• Poor contact of
ECM connector
• Poor contact of
coupling connector
3
CHECK HARNESS BETWEEN ECM AND
SECONDARY AIR COMBINATION VALVE
CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance of harness between
ECM connector and secondary air combination
valve RH or LH connector.
Connector & terminal
Models without SI-DRIVE
(B137) No. 9 — (E41) No. 2:
Models with SI-DRIVE
(B137) No. 9 — (E40) No. 2:
Is the resistance less than 1 Ω? Go to step
4.
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
ECM
connector
and secondary air
combination valve
RH or LH connec-
tor
• Poor contact of
coupling connector
4
CHECK HARNESS BETWEEN ECM AND
SECONDARY AIR COMBINATION VALVE
CONNECTOR.
Measure the resistance between ECM connec-
tor and chassis ground.
Connector & terminal
(B137) No. 9 — Chassis ground:
Is the resistance 1 MΩ or
more?
Go to step
5.
Repair the ground
short circuit in har-
ness between
ECM connector
and secondary air
combination valve
RH or LH connec-
tor.