Subaru 2009 IMPREZA Service Manual page 1587

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
1 CHECK SECONDARY AIR PIPING PRES-
SURE.
1) Turn the ignition switch to ON.
2) Using the Subaru Select Monitor, read sec-
ondary air piping pressure data, and compare
with the actual atmospheric pressure.
NOTE:
For detailed operation procedures, refer to
"READ CURRENT DATA FOR ENGINE". <Ref.
to EN(H4DOTC)(diag)-34, Subaru Select Moni-
tor.>
2 CHECK SECONDARY AIR PUMP.
1) Start the engine and warm up engine until
coolant temperature is higher than 75°C
(167°F).
2) Check whether the secondary air pump is
operating.
3 CHECK HARNESS BETWEEN ECM AND
SECONDARY AIR PUMP RELAY CONNEC-
TOR.
1) Turn the ignition switch to OFF.
2) Remove the secondary air pump relay from
the relay box.
3) Measure the resistance between the sec-
ondary air pump relay connector and engine
ground terminals.
Connector & terminal
(F9) No. 13 — Engine ground:
4 CHECK SECONDARY AIR PUMP RELAY.
Measure the resistance between the secondary
air pump relay terminals.
Terminals
No. 14 — No. 11:
Check
Is the actual difference with
atmospheric pressure
50 mmHg (6.7 kPa, 2.0 inHg,
0.97 psig) or more?
Is the secondary air pump oper-
ating?
Is the resistance 1 M or
more?
Is the resistance 1 M or
more?
EN(H4DOTC)(diag)-366
Yes No
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
may be the cause.
Go to step 3. Replace the sec-
ondary air combi-
nation valve LH.
<Ref. to
EC(H4DOTC)-25,
Secondary Air
Combination
Valve.>
Go to step 4. Repair the short
circuit to ground in
harness between
ECM and second-
ary air pump relay
connector.
Repair the short Replace the sec-
circuit to power in ondary air pump
the harness relay. <Ref. to
between second- EN(H4DOTC)(diag)
ary air pump relay -8, Electrical Com-
and secondary air ponent Location.>
pump connector.