Subaru Impreza 2004 Service Manual page 112

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(H4DOTC)(diag)-32, Subaru
Select Monitor.>
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), (i11) and ECM connector.
3)Measure the resistance between ECM and
chassis ground.
Connector & terminal
(B135) No. 25 — Chassis ground:
Check
Does the speedometer and
tachometer operate normally?
Is the voltage less than 0.12
V?
Shake the ECM harness and
connector, while monitoring
value of Subaru Select Moni-
tor. Does the voltage change?
Is the voltage more than 0.12
V?
Is the resistance more than 1
MΩ?
EN(H4DOTC)(diag)-191
ENGINE (DIAGNOSTICS)
Yes
Go to step 2. Repair or replace
the combination
meter. <Ref. to
IDI-3, Combina-
tion Meter Sys-
tem.>
Go to step 4. Go to step 3.
Repair the poor Even if malfunction
contact in ECM indicator light
connector. 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 the ground
short circuit in har-
ness between
ECM and combi-
nation meter con-
nector.
No