Subaru 2002 IMPREZA Service Manual page 1373

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK SPEEDOMETER AND TACHOME-
TER OPERATION IN COMBINATION
METER.
2 CHECK INPUT SIGNAL FOR ECM.
1)Turn the ignition switch to ON. (engine OFF)
2)Measure the voltage between ECM connec-
tor and chassis ground.
Connector & terminal
(B135) No. 25 (+) — Chassis ground ( − − − − ):
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(TURBO)-34, Subaru Select Moni-
tor.>
4 CHECK INPUT VOLTAGE OF ECM.
1)Turn the ignition switch to OFF.
2)Separate the 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
(i10), (i12) 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:
Check
Does the speedometer and
tachometer operate normally?
Is the voltage less than 0.12
V?
Does the value change less
than 0.12 V by shaking har-
ness and connector of ECM
while monitoring the value with
Subaru Select Monitor?
Is the voltage more than 0.12
V?
Is the resistance more than 1
MΩ?
Is the resistance less than 10
Ω?
EN(TURBO)-213
ENGINE (DIAGNOSTICS)
Yes
Go to step 2. Repair or replace
the combination
meter. <Ref. to
IDI-4, Combina-
tion Meter Sys-
tem.>
Go to step 6. Go to step 3.
Repair the poor Even if MIL lights
contact in ECM up, the circuit has
connector. returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector
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 4. Go to step 7.
Go to step 6. Repair the ground
short circuit in har-
ness between
ECM and combi-
nation meter con-
nector.
Repair or replace Repair the open
the combination circuit between
meter. <Ref. to ECM and combi-
IDI-4, Combina- nation meter con-
tion Meter Sys- nector.
tem.>
NOTE:
In this case, repair
the following:
Poor contact in
coupling connector
No