SUBARU FORESTER 2004 Service Repair Manual

EN(H4DOTC 2.5)-227
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
7 CHECK SENSOR OUTPUT.
1) Connect all the connectors.
2) Turn the ignition switch to ON.
3) Measure the voltage between ECM con-
nector terminals.
Connector & terminal
(B136) No. 29 (+) — (B136) No. 35 (
−):
4) Check the voltage change by shaking the har-
ness and connector of ECM, engine harness con-
nector and electronic throttle control connector.Is the voltage more than 0.8 V? Go to step 8.Go to step 9.
8 CHECK POOR CONTACT.
Check the poor contact in connector between
ECM and electronic throttle control.Is there poor contact? Repair the poor
contact.Go to step 13.
9 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Disconnect the connectors from the elec-
tronic throttle control.
4) Measure the resistance between ECM con-
nector and electronic throttle control connector.
Connector & terminal
(B136) No. 16 — (E57) No. 5:Is the resistance less than 1
Ω?Go to step 10.Repair the open
circuit of harness
connector.
10 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
Measure the resistance between ECM connec-
tor and chassis ground.
Connector & terminal
(B136) No. 16 — Chassis ground:
(B136) No. 18 — Chassis ground:
(B136) No. 29 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 11.Repair the ground
short circuit of har-
ness.
11 CHECK SENSOR POWER SUPPLY.
1) Connect the ECM connector.
2) Turn the ignition switch to ON.
3) Measure the voltage between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 5 (+) — Engine ground (
−):
4) Check the voltage change by shaking the
harness and connector of ECM and engine
harness connector while monitoring the value
with voltage meter.Is the voltage 4.5 — 5.5 V? Go to step 12.Repair the poor
contact in ECM
connector. Replace
the ECM if defec-
tive. <Ref. to
FU(H4DOTC 2.5)-
41, Engine Con-
trol Module
(ECM).>
12 CHECK SHORT CIRCUIT IN ECM.
1) Turn the ignition switch to OFF.
2) Measure the resistance between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 4 — Engine ground:
(E57) No. 6 — Engine ground:Is the resistance more than 10
Ω?Go to step 13.Repair the poor
contact in ECM
connector.
Replace the ECM
if defective.
13 CHECK SENSOR OUTPUT.
1) Connect all the connectors.
2) Turn the ignition switch to ON.
3) Read the data of main throttle sensor signal
using Subaru Select Monitor.
4) Check the voltage change by shaking the
harness and connector of ECM, engine har-
ness connector and electronic throttle control
connector.Is the voltage 4.63 V? Go to step 14.Go to step 16. Step Check Yes No

EN(H4DOTC 2.5)-228
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
14 CHECK SENSOR OUTPUT.
1) Read the data of sub throttle sensor signal
using Subaru Select Monitor.
2) Check the voltage change by shaking the
harness and connector of ECM, engine har-
ness connector and electronic throttle control
connector.Is the voltage 4.73 V? Go to step 15.Go to step 16.
15 CHECK POOR CONTACT.
Check the poor contact in connector between
ECM and electronic throttle control.Is there poor contact? Repair the poor
contact.Go to step 21.
16 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Disconnect the connectors from the elec-
tronic throttle control.
4) Measure the resistance between ECM con-
nector and electronic throttle control connector.
Connector & terminal
(B136) No. 18 — (E57) No. 6:
(B136) No. 29 — (E57) No. 4:
(B136) No. 35 — (E57) No. 3:Is the resistance less than 1
Ω?Go to step 17.Repair the open
circuit of harness
connector.
17 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Connect the ECM connector.
2) Measure the resistance between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 3 — Engine ground:Is the resistance less than 5
Ω?Go to step 18.Repair the poor
contact in ECM
connector.
Replace the ECM
if defective.
18 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Turn the ignition switch to ON.
2) Measure the voltage between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 5 (+) — Engine ground (
−):
3) Check the voltage change by shaking the
harness and connector of ECM and engine
harness connector while monitoring the value
with voltage meter.Is the voltage more than 10 V? Go to step 19.Repair battery
short circuit in har-
ness between ECM
connector and elec-
tronic throttle con-
trol connector.
19 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Measure the voltage between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 4 (+) — Engine ground (
−):
(E57) No. 6 (+) — Engine ground (
−):
2) Check the voltage change by shaking the
harness and connector of ECM and engine
harness connector while monitoring the value
with voltage meter.Is the voltage less than 10 V? Go to step 20.Repair short circuit
in harness
between ECM
connector and
electronic throttle
control connector. Step Check Yes No

EN(H4DOTC 2.5)-229
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
20 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Turn the ignition switch to OFF.
2) Remove the ECM.
3) Measure the resistance between ECM con-
nectors.
Connector & terminal
(B136) No. 18 — (B136) No. 35:
(B136) No. 29 — (B136) No. 35:Is the resistance more than 1
MΩ?Go to step 21.Repair short circuit
to sensor power
supply.
21 CHECK SENSOR OUTPUT.
1) Turn the ignition switch to OFF.
2) Connect the connectors except of the elec-
tric control throttle relay.
3) Turn the ignition switch to ON.
4) Read the data of main throttle sensor signal
using Subaru Select Monitor.Is the voltage 0.81 — 0.87 V? Go to step 22.Repair poor contact
of electronic throt-
tle control connec-
tor. Replace the
electronic throttle
control if defective.
22 CHECK SENSOR OUTPUT.
Read the data of sub throttle sensor signal
using Subaru Select Monitor.Is the voltage 1.64 — 1.70 V? Go to step 23.Repair the poor
contact in ECM con-
nector. Replace the
electronic throttle
control if defective.
23 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL MO-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Disconnect the connectors from the elec-
tronic throttle control.
4) Measure the resistance between ECM con-
nector and electronic throttle control connector.
Connector & terminal
(B137) No. 4 — (E57) No. 1:
(B137) No. 5 — (E57) No. 2:Is the resistance less than 1
Ω?Go to step 24.Repair the open
circuit of harness
connector.
24 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL MO-
TOR.
1) Connect the connector to ECM.
2) Turn the ignition switch to ON.
3) Measure the voltage between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 1 (+) — Engine ground (
−):
(E57) No. 2 (+) — Engine ground (
−):Is the voltage less than 5 V? Go to step 25.Repair power sup-
ply short circuit in
harness between
ECM and electronic
throttle control.
25 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL MO-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance between electronic
throttle control connector and engine ground.
Connector & terminal
(E57) No. 1 — Engine ground:
(E57) No. 2 — Engine ground:Is the resistance more than 1
MΩ?Go to step 26.Repair the short
circuit of harness.
26 CHECK ELECTRONIC THROTTLE CON-
TROL MOTOR HARNESS.
Measure the resistance between electronic
throttle control connector terminals.
Connector & terminal
(E57) No. 2 — (E57) No. 1:Is the resistance more than 1
MΩ?Go to step 27.Repair the short
circuit of harness. Step Check Yes No

EN(H4DOTC 2.5)-230
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
27 CHECK ELECTRONIC THROTTLE CON-
TROL GROUND CIRCUIT.
Measure the resistance between ECM connec-
tor and engine ground.
Connector & terminal
(B137) No. 3 — Engine ground:Is the resistance less than 10
Ω?Go to step 28.Repair the open
circuit of harness.
28 CHECK ELECTRONIC THROTTLE CON-
TROL.
Measure the resistance between electronic
throttle control terminals.
Te r m i n a l s
No. 1 — No. 2:Is the resistance less than 5
Ω?Go to step 29.Repair the elec-
tronic throttle con-
trol.
29 CHECK ELECTRONIC THROTTLE CON-
TROL.
Move the throttle valve to the fully open and
fully closed positions with fingers
Check the valve returns to the specified posi-
tion when releasing fingers.Does the valve return to the
specified position?
Standard value: 3 mm (0.12 in)
from fully closed positionRepair the poor
contact in ECM
connector. Replace
the ECM if defec-
tive. <Ref. to
FU(H4DOTC 2.5)-
41, Engine Con-
trol Module
(ECM).>Repair the elec-
tronic throttle con-
trol. Step Check Yes No

EN(H4DOTC 2.5)-231
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
BY:DTC P2102 THROTTLE ACTUATOR CONTROL MOTOR CIRCUIT LOW
DTC DETECTING CONDITION:
Immediately at fault recognition
TROUBLE SYMPTOM:
 Erroneous idling
 Poor driving performance
 Engine stalls.
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H4DOTC 2.5)-42,
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC 2.5)-35, OPERATION,
Inspection Mode.>.

EN(H4DOTC 2.5)-232
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
WIRING DIAGRAM:
EN-02364
B317
34
12
B22
125678
131415169101112
34
17181920
B21
123
4
56
78
9
1011 12
1314 15 16
B83
1
23456
B135
567
82 1
94 3
10
24 22 23 2511 12 13 14 15
26 27
2816 17 18 19
20 21
29 30 31 32 33 34 35
B:
B35D6
B135 B: C:
D4 D3
C18
B1 C35
D1 B4
D2
SBF-5
2
1
3
4
E
E57
3
6 4
1
2 2
3
15
16
E
5
EE
B137 D:ECM B309
B136
B122
1
E2 B21
E3 B22 B317
E56B47 35
2 1
4 3
D5C16C29
19122018
MAIN RELAYBATTERY
ELECTRONIC
THROTTLE
CONTROL ELECTRONIC
THROTTLE
CONTROL
RELAY
B83
B122
123456783412
56
B47
B137
567
82 1
94 3
10
22 23 11 12 13 14 15
24 25
2616 17
18 19 20 21
27 28 29 30 31
D:
B136
56
782 1
94 3
10
24 22 23 2511 12 13
1415
26 27
2816
17 18 19 20 21
33 34 29
32 30
31 35
C:
B309
34
12
E57

EN(H4DOTC 2.5)-233
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK ELECTRONIC THROTTLE CON-
TROL RELAY.
1) Turn the ignition switch to OFF.
2) Remove the electronic throttle control relay.
3) Connect the battery to electronic throttle
control relay terminals No. 1 and No. 3.
4) Measure the resistance between electronic
throttle control terminals.
Te r m i n a l s
(B309) No. 2 — (B309) No. 4:Is the resistance less than 1
Ω?Go to step 2.Replace the elec-
tronic throttle con-
trol relay.
2 CHECK POWER SUPPLY OF ELECTRONIC
THROTTLE CONTROL RELAY.
Measure the voltage between electronic throt-
tle control relay connector and engine ground.
Connector & terminal
(B309) No. 1 (+) — Engine ground (
−):
(B309) No. 2 (+) — Engine ground (
−):Is the voltage more than 5 V? Go to step 3.Repair open or
ground short cir-
cuit of power sup-
ply circuit.
3 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL RE-
LAY.
1) Disconnect the connector from ECM.
2) Turn the ignition switch to ON.
3) Measure the voltage between electronic
throttle control relay connector and engine
ground.
Connector & terminal
(B309) No. 3 (+) — Engine ground (
−):Is the voltage less than 5 V? Go to step 4.Repair power sup-
ply short circuit in
harness between
ECM and elec-
tronic throttle con-
trol relay.
4 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL RE-
LAY.
1) Turn the ignition switch to OFF.
2) Measure the resistance between electronic
throttle control relay connector and chassis
ground.
Connector & terminal
(B309) No. 3 — Engine ground:
(B309) No. 4 — Engine ground:Is the resistance more than 1
MΩ?Go to step 5.Repair ground
short circuit in har-
ness between
ECM and elec-
tronic throttle con-
trol relay.
5 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL RE-
LAY.
Measure the resistance between ECM connector
and electronic throttle control relay connector.
Connector & terminal
(B135) No. 35 — (B309) No. 3:
(B137) No. 6 — (B309) No. 4:Is the resistance less than 1
Ω?Repair the poor
contact in ECM con-
nector. Replace the
ECM if defective.Repair open circuit
in harness between
ECM and electronic
throttle control relay.

EN(H4DOTC 2.5)-234
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
BZ:DTC P2103 THROTTLE ACTUATOR CONTROL MOTOR CIRCUIT HIGH
DTC DETECTING CONDITION:
Immediately at fault recognition
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H4DOTC 2.5)-42,
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC 2.5)-35, OPERATION,
Inspection Mode.>.
WIRING DIAGRAM:
EN-02364
B317
34
12
B22
125678
131415169101112
34
17181920
B21
123
4
56
78
9
1011 12
1314 15 16
B83
1
23456
B135
567
82 1
94 3
10
24 22 23 2511 12 13 14 15
26 27
2816 17 18 19
20 21
29 30 31 32 33 34 35
B:
B35D6
B135 B: C:
D4 D3
C18
B1 C35
D1 B4
D2
SBF-5
2
1
3
4
E
E57
3
6 4
1
2 2
3
15
16
E
5
EE
B137 D:ECM B309
B136
B122
1
E2 B21
E3 B22 B317
E56B47 35
2 1
4 3
D5C16C29
19122018
MAIN RELAYBATTERY
ELECTRONIC
THROTTLE
CONTROL ELECTRONIC
THROTTLE
CONTROL
RELAY
B83
B122
123456783412
56
B47
B137
567
82 1
94 3
10
22 23 11 12 13 14 15
24 25
2616 17
18 19 20 21
27 28 29 30 31
D:
B136
56
782 1
94 3
10
24 22 23 2511 12 13
1415
26 27
2816
17 18 19 20 21
33 34 29
32 30
31 35
C:
B309
34
12
E57

EN(H4DOTC 2.5)-235
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
CA:DTC P2109 THROTTLE/PEDAL POSITION SENSOR A MINIMUM STOP PER-
FORMANCE
NOTE:
For diagnostic procedure, refer to DTC P2101. <Ref. to EN(H4DOTC 2.5)-224, DTC P2101 THROTTLE AC-
TUATOR CONTROL MOTOR CIRCUIT RANGE/PERFORMANCE, Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>
Step Check Yes No
1 CHECK ELECTRONIC THROTTLE CON-
TROL RELAY.
1) Turn the ignition switch to OFF.
2) Remove the electronic throttle control relay.
3) Measure the resistance between electronic
throttle control relay terminals.
Te r m i n a l s
No. 2 — No. 4:Is the resistance more than 1
MΩ?Go to step 2.Replace the elec-
tronic throttle con-
trol relay.
2 CHECK POWER SUPPLY SHORT CIRCUIT
OF ELECTRONIC THROTTLE CONTROL
RELAY.
1) Turn the ignition switch to ON.
2) Measure the voltage between electronic
throttle control relay connector and engine
ground.
Connector & terminal
(B309) No. 4 (+) — Engine ground (
−):Is the voltage more than 5 V? Go to step 3.Repair power sup-
ply short circuit in
harness between
ECM and elec-
tronic throttle con-
trol relay.
3 CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL RE-
LAY.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance between ECM con-
nector and engine ground.
Connector & terminal
(B135) No. 35 — Engine ground:Is the resistance more than 1
MΩ?Repair the poor
contact in ECM
connector.
Replace the ECM
if defective.Repair ground
short circuit in har-
ness between
ECM and elec-
tronic throttle con-
trol relay.

EN(H4DOTC 2.5)-236
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
CB:DTC P2122 THROTTLE/PEDAL POSITION SENSOR/SWITCH “D” CIRCUIT
LOW INPUT
DTC DETECTING CONDITION:
Immediately at fault recognition
TROUBLE SYMPTOM:
 Erroneous idling
 Poor driving performance
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H4DOTC 2.5)-42,
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC 2.5)-35, OPERATION,
Inspection Mode.>.
WIRING DIAGRAM:
EN-02377
B315B83
B21
E
C:ECM
B136
B137
D:
C:B136
B137
D:
B122
B21
E2
B315
1
3
354126 C15
C17
C34
C16
C28
C35
D1D2
16
123
4
56
78
9
1011 12
1314 15 16
123456
B122
56
782 1
94 310
24 22 23 2511 12 13
1415
26 27
2816
17 18 19 20 21
33 34 29
32 30
31 35
567
82 1
94 310
22 23 11 12 13 14 15
24 25
2616 17
18 19 20 21
27 28 29 30 31
MAINSUB
ACCELERATOR
PEDAL
POSITION
SENSOR
B833
112345678