Subaru 2002 IMPREZA Service Manual page 319

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
ENGINE (DIAGNOSTICS)
Yes
20 to step 2.
3epair the con-
Step
CHECK GROUND CIRCUIT OF ECM.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from ECM.
3)Measure the resistance of harness between
ECM connector and chassis ground.
Connector & terminal
(8137) No. 8
-
Chassis ground:
(8137)
No.
9
-
Chassis ground:
No
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
Go to step 3.
!
CHECK CURRENT DATA.
1)Start the engine.
2)Read the data of rear oxygen sensor heater
current using Subaru Select Monitor or OBD-ll
general scan tool.
NOTE:
*Subaru Select Monitor
For detailed operation procedure, refer to the
"QEAD CURRENT DATA FOR ENGINE". <Ref.
to EN(D0HC TURBO)-38, Subaru Select Mon-
itor.>
*OBD-I1 scan tool
For detailed operation procedures, refer to the
OBD-ll General Scan Tool Instruction Manual.
CHECK OUTPUT SIGNAL FROM ECM.
1)Start and idle the engine.
2)Measure the voltage between ECM connec-
tor and chassis ground.
I
Connector & terminal
(8136) No. 13 (+)
-
Chassis ground
( - ) I
CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
I
Connector & terminal
(8136)
No. 13 (+)
-
Chassis ground ( - ) :
CHECK OUTPUT SIGNAL FROM ECM.
1)Disconnect the connector from rear oxygen
sensor.
2)Measure the voltage between ECM connec-
tor and chassis ground.
1
Connector & terminal
( 8 136)
No. 13 (+)
-
Chassis ground (-):
loes the voltage change less
han 1 .O V by shaking harness
ind connector of ECM while
nonitoring the value with volt-
ige meter?
s the voltage less than 1
.O
V?
Check
s the resistance less than 5
2?
Repair poor con-
tact in ECM con-
nector.
Go to step 5.
Replace the ECM. Repair battery
<Ref. to FU(D0HC short circuit in har-
TURBO)-47, ness between
Engine Control ECM and rear oxy-
Module.> gen sensor con-
nector. After
repair, replace the
ECM. <Ref. to
FU(D0HC
Engine Control
Module.>
TURBO)-47,
s the value more than 0.2 A?
Go to step
4.
EN(D0HC TURBO)-95