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Subaru Legacy III (2000-2003 year). Manual - part 501

EN(H4DOSTC)-174

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

AO:DTC P0852 — NEUTRAL SWITCH INPUT CIRCUIT HIGH (AT MODEL) —

• DTC DETECTING CONDITION:

• Two consecutive driving cycles with fault

• TROUBLE SYMPTOM:

• Erroneous idling

CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode<Ref. to EN(H4DOSTC)-35,
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOSTC)-33, OPERATION, In-
spection Mode.> .
• WIRING DIAGRAM:

EN-01003

INHIBITOR SWITCH

B12

B14

B12

1 2 3 4 5 6
7 8 9 10 11 12

B134

ECM

STARTER MOTOR

1 2 3 4
5 6 7 8
9 10 11 12

B134

1 2 3 4

10 11 12

19 20 21

14 15

8 9

16 17

EN(H4DOSTC)-175

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

Step

Value

Yes

CHECK ANY OTHER DTC ON DISPLAY.
Is any other DTC displayed?

DTC indicated.

Inspect the rele-
vant DTC using
“List of Diagnos-
tics Trouble Code
(DTC)”. <Ref. to
EN(H4DOSTC)-
62, List of Diag-
nostic Trouble
Code (DTC).>

Go to step 2.

CHECK INPUT SIGNAL FOR ECM.
1) Turn ignition switch to ON.
2) Measure voltage between ECM and chas-

sis ground in select level “N” and “P” posi-
tions.

Connector & terminal

(B134) No. 8 (+) — Chassis ground

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

1 V

Go to step 3.

Go to step 5.

CHECK INPUT SIGNAL FOR ECM.
Measure voltage between ECM and chassis
ground in select level “N” and “P” positions.

Connector & terminal

(B134) No. 8 (+) — Chassis ground

Is the measured value within the specified
range?

4.5 - 5.5 V

Go to step 4.

Go to step 5.

CHECK POOR CONTACT.
Check poor contact in ECM connector.
Is there poor contact in ECM connector.

There is poor contact.

Repair poor con-
tact in ECM con-
nector.

Contact SUBARU
distributor service.

NOTE:
Inspection by DTM
is required, be-
cause probable
cause is deteriora-
tion of multiple
parts.

CHECK HARNESS BETWEEN ECM AND IN-
HIBITOR SWITCH CONNECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from ECM and inhibi-

tor switch.

3) Measure resistance of harness between

ECM and inhibitor switch connector.

Connector & terminal

(B134) No. 8 — (T7) No. 12:

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 in
harness between
ECM and inhibitor
switch connector
• Poor contact in
coupling connector
• Poor contact in
inhibitor switch
connector
• Poor contact in
ECM connector

EN(H4DOSTC)-176

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

CHECK INHIBITOR SWITCH GROUND LINE.
Measure resistance of harness between inhibi-
tor switch connector and engine ground.

Connector & terminal

(T7) No. 7 — Engine ground:

Is the measured value less than the specified
value?

Ω

Go to step 7.

Repair open circuit
in harness
between inhibitor
switch connector
and starter motor
ground line.

NOTE:
In this case, repair
the following:
• Open circuit in
harness between
inhibitor switch
connector and
starter motor
grond line
• Poor contact in
satrter motor con-
nector
• Poor contact in
starter motor
ground
• Starter motor