Subaru Legacy 2002 Service Manual page 767

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Engine (Diagnostics)
No.
1 CHECK OUTPUT SIGNAL FROM ECM.
1) Turn ignition switch to OFF.
2) Connect test mode connector at the lower
portion of instrument panel (on the driver's
side), to the side of the center console box.
3) Turn ignition switch to ON.
4) While operating radiator fan relay, measure
voltage between ECM and chassis ground.
NOTE:
Radiator fan relay operation can be executed
using Subaru Select Monitor. For procedure,
refer to "Compulsory Valve Operation Check
Mode". <Ref. to EN-46, Compulsory Valve
Operation Check Mode.>
Connector & terminal
(B134) No. 3 (+) — Chassis ground (−):
2 CHECK SHORT CIRCUIT IN RADIATOR
FAN RELAY CONTROL CIRCUIT.
1) Turn ignition switch to OFF.
2) Remove main fan relay and sub fan relay.
(with A/C models)
3) Disconnect test mode connector.
4) Turn ignition switch to ON.
5) Measure voltage between ECM and chas-
sis ground.
Connector & terminal
(B134) No. 3 (+) — Chassis ground (−):
3 CHECK MAIN FAN RELAY.
1) Turn ignition switch to OFF.
2) Remove main fan relay.
3) Measure resistance between main fan
relay terminals.
Terminal
No. 7 — No. 8:
4 CHECK SUB FAN RELAY.
1) Remove sub fan relay.
2) Measure resistance between sub fan relay
terminals.
Terminal
No. 17 — No. 18
5 CHECK POOR CONTACT.
Check poor contact in ECM connector.
Step
Does voltage change
between 0 and 10 V?
Is the voltage more than 10
V?
Is the resistance less than
1 Ω?
Is the resistance less than
1 Ω?
Is there poor contact in
ECM connector?
EN-250
Check Yes
Even if MIL lights
up, the circuit has
returned to a nor-
mal condition at
this time. In this
case, repair poor
contact in ECM
connector.
Repair battery
short circuit in
radiator fan relay
control circuit.
After repair,
replace ECM.
<Ref. to FU-51,
Engine Control
Module.>
Replace main fan
relay and ECM.
<Ref. to FU-51,
Engine Control
Module.>
Replace sub fan
relay and ECM.
<Ref. to FU-51,
Engine Control
Module.>
Repair poor con-
tact in ECM con-
nector.
No
Go to step 2.
Go to step 3.
Go to step 4.
Go to step 5.
Replace ECM.
<Ref. to FU-51,
Engine Control
Module.>