SUBARU FORESTER 2004 Service Repair Manual

EN(H4SO)-213
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK ANY OTHER DTC ON DISPLAY.Is DTC P0705 displayed? Inspect the DTC
using “List of Diag-
nostic Trouble
Code (DTC)”.
EN(H4SO)-72, List
of Diagnostic Trou-
ble Code (DTC).>Go to step 2.
2 CHECK INPUT SIGNAL FROM ECM.
1) Turn the ignition switch to ON.
2) Shift the select lever to other than “N” and
“P” ranges.
3) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B136) No. 21 (+) — Chassis ground (
−):Is the voltage more than 10 V? Even if the mal-
function indicator
light illuminates,
the circuit has
returned to a nor-
mal condition at
this time.Go to step 3.
3 CHECK HARNESS BETWEEN ECM AND
TRANSMISSION HARNESS CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM and
transmission harness connector (T3).
3) Measure the resistance of harness
between ECM connector and chassis ground.
Connector & terminal
(B136) No. 21 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 4.Repair ground
short circuit in har-
ness between
ECM and trans-
mission harness
connector.
4 CHECK TRANSMISSION HARNESS CON-
NECTOR.
1) Disconnect the connector from inhibitor
switch.
2) Measure the resistance of harness
between transmission harness connector and
engine ground.
Connector & terminal
(T3) No. 12 — Engine ground:Is the resistance more than 1
MΩ?Go to step 5.Repair ground
short circuit in har-
ness between
transmission har-
ness and inhibitor
switch connector.
5 CHECK INHIBITOR SWITCH.
Measure the resistance between inhibitor
switch connector receptacle’s terminals with
select lever at other than “N” and “P” range.
Te r m i n a l s
No. 7 — No. 12:Is the resistance more than 1
MΩ?Go to step 6.Replace inhibitor
switch. 4AT-51, Inhibitor
Switch.>
6 CHECK SELECTOR CABLE CONNECTION.Is there any fault in selector
cable connection to inhibitor
switch?Repair the select
cable connection.
INSPECTION,
Select Cable.>Contact the SUB-
ARU dealer.
N
OTE:
Inspection by DTM
is required, because
probable cause is
deterioration of mul-
tiple parts.

EN(H4SO)-214
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
BM:DTC P0851 NEUTRAL SWITCH INPUT CIRCUIT LOW (MT 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 ERATION, Clear Memory Mode.> and Inspection Mode tion Mode.>.
WIRING DIAGRAM:
EN-00282
B12T3
B14
T7INHIBITOR SWITCH
STARTER MOTOR
PRND321
12
7
12
11
B12
T7
123456789101112
123
4
56
78
9
1011 12
B136ECM
21
16
E2
B21MT
AT
NEUTRAL
POSITION
SWITCH
12
B25
B21
12345678910111213141516
B136
5
2
84
3923 20 211011
221617
24
2512136
261915
14
1
7
18
B25
T2
B25
T212
LHD
LHDRHD
RHD
B25B25
T221
LHD
LHDRHD
RHD T2

EN(H4SO)-215
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK INPUT SIGNAL FROM ECM.
1) Turn the ignition switch to ON.
2) Place the shift lever in neutral.
3) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B136) No. 21 (+) — Chassis ground (
−):Is the voltage more than 10 V? Go to step 2.Go to step 4.
2 CHECK INPUT SIGNAL FROM ECM.
1) Place the shift lever except in neutral.
2) Measure the voltage between ECM and
chassis ground.
Connector & terminal
(B136) No. 21 (+) — Chassis ground (
−):Is the voltage less than 1 V? Go to step 3.Go to step 4.
3 CHECK POOR CONTACT.
Check poor contact in ECM connector.Is there poor contact in ECM
connector?Repair the poor
contact in ECM
connector.Contact the SUB-
ARU dealer.
4 CHECK NEUTRAL POSITION SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from transmis-
sion harness.
3) Place the shift lever in neutral.
4) Measure the resistance between transmis-
sion harness and connector terminals.
Connector & terminal
(T2) No. 1 — No. 2:Is the resistance more than 1
MΩ?Go to step 5.Repair short circuit
in transmission
harness or replace
the neutral position
switch.
5 CHECK NEUTRAL POSITION SWITCH.
1) Place the shift lever except in neutral.
2) Measure the resistance between transmis-
sion harness connector terminals.Is the resistance less than 1
Ω?Go to step 6.Repair short circuit
in transmission
harness or replace
the neutral position
switch.
6 CHECK HARNESS BETWEEN ECM AND
NEUTRAL POSITION SWITCH CONNEC-
TOR.
Measure the resistance between ECM and
chassis ground.
Connector & terminal
(B136) No. 21 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 7.Repair ground
short circuit in har-
ness between
ECM and trans-
mission harness
connector.
7 CHECK HARNESS BETWEEN ECM AND
NEUTRAL POSITION SWITCH CONNEC-
TOR.
1) Disconnect the connector from ECM.
2) Measure the resistance of harness
between ECM and transmission harness con-
nector.
Connector & terminal
LHD MODEL
(B136) No. 21 — (B25) No. 1:
RHD MODEL
(B136) No. 21 — (B25) No. 2:Is the resistance less than 1
Ω?Go to step 8.Repair open circuit
in harness
between ECM and
transmission har-
ness connector.

EN(H4SO)-216
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
8 CHECK HARNESS BETWEEN ECM AND
NEUTRAL POSITION SWITCH CONNEC-
TOR.
Measure the resistance of harness between
transmission harness connector and engine
ground.
Connector & terminal
LHD MODEL
(B25) No. 2 — Engine ground:
RHD MODEL
(B25) No. 1 — Engine ground:Is the resistance less than 5
Ω?Go to step 9.Repair open circuit
between transmis-
sion harness con-
nector and engine
ground terminal.
9 CHECK POOR CONTACT.
Check poor contact in transmission harness
connector.Is there poor contact in trans-
mission harness connector?Repair poor con-
tact in transmis-
sion harness
connector.Contact the SUB-
ARU dealer. Step Check Yes No

EN(H4SO)-217
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
BN:DTC P0852 NEUTRAL SWITCH INPUT CIRCUIT HIGH
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 ERATION, Clear Memory Mode.> and Inspection Mode tion Mode.>.
WIRING DIAGRAM:
EN-00282
B12T3
B14
T7INHIBITOR SWITCH
STARTER MOTOR
PRND321
12
7
12
11
B12
T7
123456789101112
123
4
56
78
9
1011 12
B136ECM
21
16
E2
B21MT
AT
NEUTRAL
POSITION
SWITCH
12
B25
B21
12345678910111213141516
B136
5
2
84
3923 20 211011
221617
24
2512136
261915
14
1
7
18
B25
T2
B25
T212
LHD
LHDRHD
RHD
B25B25
T221
LHD
LHDRHD
RHD T2

EN(H4SO)-218
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK ANY OTHER DTC ON DISPLAY.Is any other DTC displayed? Inspect the DTC
using “List of Diag-
nostic Trouble
Code (DTC)”.
EN(H4SO)-72, List
of Diagnostic Trou-
ble Code (DTC).>Go to step 2.
2 CHECK INPUT SIGNAL FROM ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM and
chassis ground with select lever at “N” and “P”
ranges.
Connector & terminal
(B136) No. 21 (+) — Chassis ground (
−):Is the voltage less than 1 V? Go to step 3.Go to step 5.
3 CHECK INPUT SIGNAL FROM ECM.
Measure the voltage between ECM and chas-
sis ground with select lever at except “N” and
“P” ranges.
Connector & terminal
(B136) No. 21 (+) — Chassis ground (
−):Is the voltage between 4.5 —
5.5 V?Go to step 4.Go to step 5.
4 CHECK POOR CONTACT.
Check poor contact in ECM connector.Is there poor contact in ECM
connector?Repair the poor
contact in ECM
connector.Replace the ECM.
FU(H4SO)-44,
Engine Control
Module (ECM).>
5 CHECK INPUT SIGNAL FROM ECM.
Measure the voltage between ECM and chas-
sis ground.
Connector & terminal
(B136) No. 21 (+) — Chassis ground (
−):Is the voltage more than 10 V? Repair the battery
short circuit in har-
ness between
ECM and inhibitor
switch connector.Go to step 6.
6 CHECK HARNESS BETWEEN ECM AND IN-
HIBITOR SWITCH CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM and
inhibitor switch.
3) Measure the resistance of harness
between ECM and inhibitor switch connector.
Connector & terminal
(B136) No. 21 — (T7) No. 12:Is the resistance less than 1
Ω?Go to step 7.Repair harness
and connector.
N
OTE:
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.
7 CHECK INHIBITOR SWITCH GROUND LINE.
Measure the resistance of harness between
inhibitor switch connector and engine ground.
Connector & terminal
(T7) No. 7 — Engine ground:Is the resistance less than 5
Ω?Go to step 8.Repair open circuit
in harness
between inhibitor
switch connector
and ground line.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
inhibitor switch
connector and
ground line

EN(H4SO)-219
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
8 CHECK INHIBITOR SWITCH.
Measure the resistance between inhibitor
switch connector receptacle’s terminals with
select lever at “N” and “P” ranges.
Te r m i n a l s
No. 7 — No. 12:Is the resistance less than 1
Ω?Go to step 9.Replace inhibitor
switch. 4AT-51, Inhibitor
Switch.>
9 CHECK SELECTOR CABLE CONNECTION.Is there any fault in selector
cable connection to inhibitor
switch?Repair selector
cable connection.
INSPECTION,
Select Cable.>Contact the SUB-
ARU dealer.
N
OTE:
Inspection by DTM
is required, because
probable cause is
deterioration of mul-
tiple parts. Step Check Yes No

EN(H4SO)-220
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
BO:DTC P0864 TCM COMMUNICATION CIRCUIT RANGE/PERFORMANCE
DTC DETECTING CONDITION:
Two consecutive driving cycles with fault
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode ERATION, Clear Memory Mode.> and Inspection Mode tion Mode.>.
WIRING DIAGRAM:
EN-00283
B134
10
ECM
B55TCM
17
B55
B134
1234567891011121314151617181920212223242526272829303132333435
123410 11 12
19 20 21135614 1578916 17 18
22 23 24

EN(H4SO)-221
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK DRIVING CONDITION.
1) Start and warm-up the engine until the radi-
ator fan makes one complete rotation.
2) Drive the vehicle.Is the AT shift control function-
ing properly?Go to step 2.Replace the TCM.
Transmission Con-
trol Module
(TCM).>
2 CHECK ACCESSORY.Are car phone/CB installed on
vehicle?Repair grounding
line of car phone
or CB system.Replace the TCM.
Transmission Con-
trol Module
(TCM).>

EN(H4SO)-222
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
BP:DTC P0865 TCM COMMUNICATION CIRCUIT LOW
DTC DETECTING CONDITION:
Two consecutive driving cycles with fault
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode ERATION, Clear Memory Mode.> and Inspection Mode tion Mode.>.
WIRING DIAGRAM:
EN-00283
B134
10
ECM
B55TCM
17
B55
B134
1234567891011121314151617181920212223242526272829303132333435
123410 11 12
19 20 21135614 1578916 17 18
22 23 24