Subaru Legacy 2003 Service Manual page 2034

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK POWER SUPPLY CIRCUIT TO FUEL
PUMP CONTROLLER.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from fuel pump
controller.
3) Turn the ignition switch to ON.
4) Measure the voltage between fuel pump
controller and chassis ground.
Connector & terminal
(R122) No. 10 (+) — Chassis ground (-):
Does the measured value exceed the spec-
ified value?
2 CHECK GROUND CIRCUIT OF FUEL PUMP
CONTROLLER.
1) Turn the ignition switch to OFF.
2) Measure the resistance of harness
between fuel pump controller and chassis
ground.
Connector & terminal
(R122) No. 5 — Chassis ground:
Is the measured value less than the speci-
fied value?
3 CHECK HARNESS BETWEEN FUEL PUMP
CONTROLLER AND FUEL PUMP CONNEC-
TOR.
1) Disconnect the connector from fuel pump.
2) Measure the resistance of harness
between fuel pump controller and fuel
pump connector.
Connector & terminal
(R122) No. 7 — (R58) No. 2:
(R122) No. 6 — (R58) No. 1:
Is the measured value less than the speci-
fied value?
4 CHECK HARNESS BETWEEN FUEL PUMP
CONTROLLER AND FUEL PUMP CONNEC-
TOR.
Measure the resistance of harness between
fuel pump controller and chassis ground.
Connector & terminal
(R122) No. 7 — Chassis ground:
(R122) No. 6 — Chassis ground:
Does the measured value exceed the specified
value?
Value
10 V
5 Ω
1 Ω
1 MΩ
EN(H4DOSTC)-195
ENGINE (DIAGNOSTICS)
Yes
Go to step 2. Repair the power
supply circuit.
NOTE:
In this case repair
the following:
• Open or ground
short circuit in har-
ness between fuel
pump relay and
fuel pump control-
ler.
• Poor contact in
fuel pump control-
ler connector.
• Poor contact in
fuel pump relay
connector.
Go to step 3. Repair the har-
ness and connec-
tor.
NOTE:
In this case, repair
the following:
• Open circuit
between fuel
pump controller
and chassis
ground.
• Poor contact in
fuel pump control-
ler connector.
Go to step 4. Repair the open
circuit between
fuel pump control-
ler and fuel pump.
Go to step 5. Repair the ground
short circuit
between fuel
pump controller
and fuel pump.
No