Subaru Impreza 2003 Service Manual page 589

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
3 CHECK INPUT SIGNAL FOR ECM. (USING
SUBARU SELECT MONITOR.)
Read the data of fuel level sensor signal using
Subaru Select Monitor.
NOTE:
•Subaru Select Monitor
For detailed operation procedure, refer to the
"READ CURRENT DATA FOR ENGINE".
<Ref. to EN(H4SO)-31, Subaru Select Moni-
tor.>
4 CHECK INPUT VOLTAGE OF ECM.
1)Turn the ignition switch to OFF.
2)Separate fuel tank cord connector (R57) and
rear wiring harness connector (R15).
3)Turn the ignition switch to ON.
4)Measure the voltage of harness between
ECM connector and chassis ground.
Connector & terminal
(B135) No. 25 (+) — Chassis ground ( − − − − ):
5 CHECK HARNESS BETWEEN ECM AND
COMBINATION METER.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from connector
(i11) and ECM connector.
3)Measure the resistance between ECM and
chassis ground.
Connector & terminal
(B135) No. 25 — Chassis ground:
6 CHECK HARNESS BETWEEN ECM AND
COMBINATION METER.
Measure the resistance between ECM and
combination meter connector.
Connector & terminal
(B135) No. 25 — (i12) No. 2:
7 CHECK FUEL TANK CORD.
1)Disconnect the connector from fuel pump
assembly.
2)Measure the resistance between fuel pump
assembly and chassis ground.
Connector & terminal
(R58) No. 3 — Chassis ground:
Check
Is the voltage less than 0.12 V
by shaking the harness and
connector of ECM?
Is the voltage more than 0.12
V?
Is the resistance more than 1
MΩ?
Is the resistance less than 10
Ω?
Is the resistance more than 1
MΩ?
EN(H4SO)-177
ENGINE (DIAGNOSTICS)
Yes
Repair poor con- Even if malfunc-
tact in ECM con- tion indicator light
nector. lights up, the cir-
cuit has returned
to a normal condi-
tion at this time. A
temporary poor
contact of the con-
nector may be the
cause.
NOTE:
In this case, repair
the following:
• Poor contact in
combination meter
connector
• Poor contact in
ECM connector
• Poor contact in
coupling connec-
tors
Go to step 5. Go to step 6.
Go to step 7. Repair ground
short circuit in har-
ness between
ECM and combi-
nation meter con-
nector.
Repair or replace Repair open circuit
the combination between ECM and
meter. <Ref. to combination meter
IDI-3, Combina- connector.
tion Meter Sys-
NOTE:
tem.>
In this case, repair
the following:
Poor contact in
coupling connector
Go to step 8. Repair ground
short circuit in fuel
tank cord.
No