Subaru Legacy III (2000-2003 year). Manual - part 349

EN(H6DO)-198

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

Step

Value

Yes

CHECK POWER SUPPLY CIRCUIT TO FUEL
PUMP CONTROLLER.
1) Turn ignition switch to OFF.
2) Disconnect connector from fuel pump con-

troller.

3) Turn ignition switch to ON.
4) Measure voltage between fuel pump con-

troller and chassis ground.

Connector & terminal

(R122) No. 10 (+) — Chassis ground (

−−−−

Does the measured value exceed the spec-
ified value?

10 V

Go to step 2.

Repair power sup-
ply 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.

CHECK GROUND CIRCUIT OF FUEL PUMP
CONTROLLER.
1) Turn ignition switch to OFF.
2) Measure 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?

Ω

Go to step 3.

Repair harness
and connector.

NOTE:
In this case, repair
the following:
• Open circuit
between fuel
pump controller
and chassis
ground.
• Poor contact in
fuel pump control-
ler connector.

CHECK HARNESS BETWEEN FUEL PUMP
CONTROLLER AND FUEL PUMP CONNEC-
TOR.
1) Disconnect connector from fuel pump.
2) Measure resistance of harness between

fuel pump controller and fuel pump connec-
tor.

Connector & terminal

(R122) No. 7 — (R58) No. 2:
(R122) No. 6 — (R58) No. 1:

Is the measured value less than the speci-
fied value?

Ω

Go to step 4.

Repair open circuit
between fuel
pump controller
and fuel pump.

CHECK HARNESS BETWEEN FUEL PUMP
CONTROLLER AND FUEL PUMP CONNEC-
TOR.
Measure 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?

1 M

Ω

Go to step 5.

Repair ground
short circuit
between fuel
pump controller
and fuel pump.

EN(H6DO)-199

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

CHECK HARNESS BETWEEN FUEL PUMP
CONTROLLER AND ECM CONNECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from ECM.
3) Measure resistance of harness between

fuel pump controller and ECM connector.

Connector & terminal

(R122) No. 9 — (B135) No. 12:
(R122) No. 8 — (B136) No. 16:

Is the measured value less than the speci-
fied value?

Ω

Go to step 6.

Repair harness
and connector.

NOTE:
In this case, repair
the following:
• Open circuit
between fuel
pump controller
and ECM.
• Poor contact in
fuel pump control-
ler and ECM con-
nector.

CHECK HARNESS BETWEEN FUEL PUMP
CONTROLLER AND ECM CONNECTOR.
Measure resistance of harness between fuel
pump controller and chassis ground.

Connector & terminal

(R122) No. 9 — Chassis ground:
(R122) No. 8 — Chassis ground:

Does the measured value exceed the specified
value?

1 M

Ω

Go to step 7.

Repair ground
short circuit
between fuel
pump controller
and ECM.

CHECK POOR CONTACT.
Check poor contact in ECM and fuel pump
controller connector.
Is there poor contact in ECM and fuel pump
controller connector.

There is poor contact.

Repair poor con-
tact in ECM and
fuel pump control-
ler.

Replace fuel pump
controller. <Ref. to
FU(H6DO)-49,
Fuel Pump Con-
troller.>

Step

Value

Yes

EN(H6DO)-200

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

AJ:DTC P0301 — CYLINDER 1 MISFIRE DETECTED —

NOTE:
For the diagnostic procedure, refer to DTC P0306. <Ref. to EN(H6DO)-202, DTC P0306 — CYLINDER 6
MISFIRE DETECTED —, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>

AK:DTC P0302 — CYLINDER 2 MISFIRE DETECTED —