SUBARU FORESTER 2004 Service Repair Manual

EN(H4DOTC 2.5)-67
ENGINE (DIAGNOSTIC)
List of Diagnostic Trouble Code (DTC)
P0512 Starter Request Circuit <Ref. to EN(H4DOTC 2.5)-155, DTC P0512 STARTER REQUEST CIRCUIT,
Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0513 Incorrect Immobilizer Key <Ref. to IM-20, DTC P0513 INCORRECT IMMOBILIZER KEY, Diagnostics
Procedure with Diagnostic Trouble Code (DTC).>
P0519 Idle Control System Malfunction
(Fail-Safe)<Ref. to EN(H4DOTC 2.5)-157, DTC P0519 IDLE CONTROL SYSTEM
MALFUNCTION (FAIL-SAFE), Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P0545 Exhaust Gas Temperature Sensor
Circuit Low-Bank 1<Ref. to EN(H4DOTC 2.5)-160, DTC P0545 EXHAUST GAS TEMPERA-
TURE SENSOR CIRCUIT LOW - BANK 1, Diagnostic Procedure with Diag-
nostic Trouble Code (DTC).>
P0546 Exhaust Gas Temperature Sensor
Circuit High-Bank 1<Ref. to EN(H4DOTC 2.5)-162, DTC P0546 EXHAUST GAS TEMPERA-
TURE SENSOR HIGH - BANK 1, Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>
P0600 Serial Communication Link <Ref. to EN(H4DOTC 2.5)-165, DTC P0600 SERIAL COMMUNICATION
LINK, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0604 Internal Control Module Random
Access Memory (RAM) Error<Ref. to EN(H4DOTC 2.5)-167, DTC P0604 INTERNAL CONTROL MOD-
ULE READ ACCESS MEMORY (RAM) ERROR, Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>
P0605 Internal Control Module Read
Access Memory (RAM) Error<Ref. to EN(H4DOTC 2.5)-169, DTC P0605 INTERNAL CONTROL MOD-
ULE READ ONLY MEMORY (ROM) ERROR, Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>
P0607 Control Module Performance <Ref. to EN(H4DOTC 2.5)-170, DTC P0607 CONTROL MODULE PERFOR-
MANCE, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0638 Throttle Actuator Control Range/
Performance (Bank 1)<Ref. to EN(H4DOTC 2.5)-172, DTC P0638 THROTTLE ACTUATOR CON-
TROL RANGE/PERFORMANCE (BANK 1), Diagnostic Procedure with Diag-
nostic Trouble Code (DTC).>
P0691 Cooling Fan 1 Control Circuit Low <Ref. to EN(H4DOTC 2.5)-173, DTC P0691 COOLING FAN 1 CONTROL
CIRCUIT LOW, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0692 Cooling Fan 1 Control Circuit High <Ref. to EN(H4DOTC 2.5)-176, DTC P0692 COOLING FAN 1 CONTROL
CIRCUIT HIGH, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P0700 Transmission Control System (MIL
Request)<Ref. to EN(H4DOTC 2.5)-178, DTC P0700 TRANSMISSION CONTROL
SYSTEM (MIL REQUEST), Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P0851 Neutral Switch Input Circuit Low <Ref. to EN(H4DOTC 2.5)-181, DTC P0851 NEUTRAL SWITCH INPUT
CIRCUIT LOW (MT MODEL), Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P0852 Neutral Switch Input Circuit High <Ref. to EN(H4DOTC 2.5)-183, DTC P0852 NEUTRAL SWITCH INPUT
CIRCUIT HIGH (AT MODEL), Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P1086 Tumble Generated Valve Position
Sensor 2 Circuit Low<Ref. to EN(H4DOTC 2.5)-188, DTC P1086 TUMBLE GENERATED VALVE
POSITION SENSOR 2 CIRCUIT LOW, Diagnostic Procedure with Diagnos-
tic Trouble Code (DTC).>
P1087 Tumble Generated Valve Position
Sensor 2 Circuit High<Ref. to EN(H4DOTC 2.5)-191, DTC P1087 TUMBLE GENERATED VALVE
POSITION SENSOR 2 CIRCUIT HIGH, Diagnostic Procedure with Diagnos-
tic Trouble Code (DTC).>
P1088 Tumble Generated Valve Position
Sensor 1 Circuit Low<Ref. to EN(H4DOTC 2.5)-193, DTC P1088 TUMBLE GENERATED VALVE
POSITION SENSOR 1 CIRCUIT LOW, Diagnostic Procedure with Diagnos-
tic Trouble Code (DTC).>
P1089 Tumble Generated Valve Position
Sensor 1 Circuit High<Ref. to EN(H4DOTC 2.5)-196, DTC P1089 TUMBLE GENERATED VALVE
POSITION SENSOR 1 CIRCUIT HIGH, Diagnostic Procedure with Diagnos-
tic Trouble Code (DTC).>
P1090 Tumble Generated Valve System 1
(Valve Open)<Ref. to EN(H4DOTC 2.5)-198, DTC P1090 TUMBLE GENERATED VALVE
SYSTEM 1 (VALVE OPEN), Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P1091 Tumble Generated Valve System 1
(Valve Close)<Ref. to EN(H4DOTC 2.5)-198, DTC P1091 TUMBLE GENERATED VALVE
SYSTEM 1 (VALVE CLOSE), Diagnostic Procedure with Diagnostic Trouble
Code (DTC).> DTC Item NOTE

EN(H4DOTC 2.5)-68
ENGINE (DIAGNOSTIC)
List of Diagnostic Trouble Code (DTC)
P1092 Tumble Generated Valve System 2
(Valve Open)<Ref. to EN(H4DOTC 2.5)-199, DTC P1092 TUMBLE GENERATED VALVE
SYSTEM 2 (VALVE OPEN), Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P1093 Tumble Generated Valve System 2
(Valve Close)<Ref. to EN(H4DOTC 2.5)-200, DTC P1093 TUMBLE GENERATED VALVE
SYSTEM 2 (VALVE CLOSE), Diagnostic Procedure with Diagnostic Trouble
Code (DTC).>
P1094 Tumble Generated Valve Signal 1
Circuit Malfunction (Open)<Ref. to EN(H4DOTC 2.5)-201, DTC P1094 TUMBLE GENERATED VALVE
SIGNAL 1 CIRCUIT MALFUNCTION (OPEN), Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>
P1095 Tumble Generated Valve Signal 1
Circuit Malfunction (Short)<Ref. to EN(H4DOTC 2.5)-203, DTC P1095 TUMBLE GENERATED VALVE
SIGNAL 1 CIRCUIT MALFUNCTION (SHORT), Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>
P1096 Tumble Generated Valve Signal 2
Circuit Malfunction (Open)<Ref. to EN(H4DOTC 2.5)-205, DTC P1096 TUMBLE GENERATED VALVE
SIGNAL 2 CIRCUIT MALFUNCTION (OPEN), Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>
P1097 Tumble Generated Valve Signal 2
Circuit Malfunction (Short)<Ref. to EN(H4DOTC 2.5)-207, DTC P1097 TUMBLE GENERATED VALVE
SIGNAL 2 CIRCUIT MALFUNCTION (SHORT), Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>
P1110 Atmospheric Pressure Sensor Cir-
cuit Malfunction (Low Input)<Ref. to EN(H4DOTC 2.5)-209, DTC P1110 ATMOSPHERIC PRESSURE
SENSOR CIRCUIT MALFUNCTION (LOW INPUT), Diagnostic Procedure
with Diagnostic Trouble Code (DTC).>
P1111 Atmospheric Pressure Sensor Cir-
cuit Malfunction (High Input)<Ref. to EN(H4DOTC 2.5)-209, DTC P1111 ATMOSPHERIC PRESSURE
SENSOR CIRCUIT MALFUNCTION (HIGH INPUT), Diagnostic Procedure
with Diagnostic Trouble Code (DTC).>
P1160 Return Spring Failure <Ref. to EN(H4DOTC 2.5)-209, DTC P1160 RETURN SPRING FAILURE,
Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P1518 Starter Switch Circuit Low Input <Ref. to EN(H4DOTC 2.5)-210, DTC P1518 STARTER SWITCH CIRCUIT
LOW INPUT, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P1544 Exhaust Gas Temperature Too High <Ref. to EN(H4DOTC 2.5)-212, DTC P1544 EXHAUST GAS TEMPERA-
TURE TOO HIGH, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P1560 Back-Up Voltage Circuit Malfunction <Ref. to EN(H4DOTC 2.5)-214, DTC P1560 BACK-UP VOLTAGE CIRCUIT
MALFUNCTION, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
P1570 ANTENNA <Ref. to IM-21, DTC P1570 ANTENNA, Diagnostics Procedure with Diag-
nostic Trouble Code (DTC).>
P1571 Reference Code Incompatibility <Ref. to IM-15, DTC P1571 REFERENCE CODE INCOMPATIBILITY, Diag-
nostics Procedure with Diagnostic Trouble Code (DTC).>
P1572 IMM Circuit Failure (Except
Antenna Circuit)<Ref. to IM-16, DTC P1572 IMM CIRCUIT FAILURE (EXCEPT ANTENNA
CIRCUIT), Diagnostics Procedure with Diagnostic Trouble Code (DTC).>
P1574 Key Communication Failure <Ref. to IM-19, DTC P1574 KEY COMMUNICATION FAILURE, Diagnostics
Procedure with Diagnostic Trouble Code (DTC).>
P1576 EGI Control Module EEPROM <Ref. to IM-20, DTC P1576 EGI CONTROL MODULE EEPROM, Diagnos-
tics Procedure with Diagnostic Trouble Code (DTC).>
P1577 IMM Control Module EEPROM <Ref. to IM-20, DTC P1577 IMM CONTROL MODULE EEPROM, Diagnos-
tics Procedure with Diagnostic Trouble Code (DTC).>
P2088 OCV Solenoid Valve Signal A Cir-
cuit Open (Bank 1)<Ref. to EN(H4DOTC 2.5)-216, DTC P2088 OCV SOLENOID VALVE SIG-
NAL A CIRCUIT OPEN (BANK 1), Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>
P2089 OCV Solenoid Valve Signal A Cir-
cuit Short (Bank 1)<Ref. to EN(H4DOTC 2.5)-218, DTC P2089 OCV SOLENOID VALVE SIG-
NAL A CIRCUIT SHORT (BANK 1), Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>
P2092 OCV Solenoid Valve Signal A Cir-
cuit Open (Bank 2)<Ref. to EN(H4DOTC 2.5)-220, DTC P2092 OCV SOLENOID VALVE SIG-
NAL A CIRCUIT OPEN (BANK 2), Diagnostic Procedure with Diagnostic
Trouble Code (DTC).>
P2093 OCV Solenoid Valve Signal A Cir-
cuit Short (Bank 2)<Ref. to EN(H4DOTC 2.5)-222, DTC P2093 OCV SOLENOID VALVE SIG-
NAL A CIRCUIT SHORT (BANK 2), Diagnostic Procedure with Diagnostic
Trouble Code (DTC).> DTC Item NOTE

EN(H4DOTC 2.5)-69
ENGINE (DIAGNOSTIC)
List of Diagnostic Trouble Code (DTC)
P2101 Throttle Actuator Control Motor Cir-
cuit Range/Performance<Ref. to EN(H4DOTC 2.5)-224, DTC P2101 THROTTLE ACTUATOR CON-
TROL MOTOR CIRCUIT RANGE/PERFORMANCE, Diagnostic Procedure
with Diagnostic Trouble Code (DTC).>
P2102 Throttle Actuator Control Motor Cir-
cuit Low<Ref. to EN(H4DOTC 2.5)-231, DTC P2102 THROTTLE ACTUATOR CON-
TROL MOTOR CIRCUIT LOW, Diagnostic Procedure with Diagnostic Trou-
ble Code (DTC).>
P2103 Throttle Actuator Control Motor Cir-
cuit High<Ref. to EN(H4DOTC 2.5)-234, DTC P2103 THROTTLE ACTUATOR CON-
TROL MOTOR CIRCUIT HIGH, Diagnostic Procedure with Diagnostic Trou-
ble Code (DTC).>
P2109 Throttle/Pedal Position Sensor A
Minimum Stop Performance<Ref. to EN(H4DOTC 2.5)-235, DTC P2109 THROTTLE/PEDAL POSITION
SENSOR A MINIMUM STOP PERFORMANCE, Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>
P2122 Throttle/Pedal Position Sensor/
Switch “D” Circuit Low Input<Ref. to EN(H4DOTC 2.5)-236, DTC P2122 THROTTLE/PEDAL POSITION
SENSOR/SWITCH “D” CIRCUIT LOW INPUT, Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>
P2123 Throttle/Pedal Position Sensor/
Switch “D” Circuit High Input<Ref. to EN(H4DOTC 2.5)-239, DTC P2123 THROTTLE/PEDAL POSITION
SENSOR/SWITCH “D” CIRCUIT HIGH INPUT, Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>
P2127 Throttle/Pedal Position Sensor/
Switch “E” Circuit Low Input<Ref. to EN(H4DOTC 2.5)-242, DTC P2127 THROTTLE/PEDAL POSITION
SENSOR/SWITCH “E” CIRCUIT LOW INPUT, Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>
P2128 Throttle/Pedal Position Sensor/
Switch “E” Circuit High Input<Ref. to EN(H4DOTC 2.5)-245, DTC P2128 THROTTLE/PEDAL POSITION
SENSOR/SWITCH “E” CIRCUIT HIGH INPUT, Diagnostic Procedure with
Diagnostic Trouble Code (DTC).>
P2135 Throttle/Pedal Position Sensor/
Switch “A”/“B” Voltage Rationality<Ref. to EN(H4DOTC 2.5)-248, DTC P2135 THROTTLE/PEDAL POSITION
SENSOR/SWITCH “A”/“B” VOLTAGE RATIONALITY, Diagnostic Procedure
with Diagnostic Trouble Code (DTC).>
P2138 Throttle/Pedal Position Sensor/
Switch “D”/“E” Voltage Rationality<Ref. to EN(H4DOTC 2.5)-253, DTC P2138 THROTTLE/PEDAL POSITION
SENSOR/SWITCH “D”/“E” VOLTAGE RATIONALITY, Diagnostic Procedure
with Diagnostic Trouble Code (DTC).> DTC Item NOTE

EN(H4DOTC 2.5)-70
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
18.Diagnostic Procedure with Diagnostic Trouble Code (DTC)
A: DTC P0031 HO2S HEATER CONTROL CIRCUIT LOW (BANK 1 SENSOR 1)
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-02359
SBF-5
B47 1 2 3 5 4 6
E
E
B21
E236
72
3
26
33
25
ECM
B134
1
3 2
4
B262
34 12
56
123
4
56
78
9
1011 12
1314 15 16
B21 B47 B262
B134
56 7
82 1
94 310
24 22 23 25 11 12 13 14 15
26 27
2816 17
18 19 20 21
33 34 29
32 30 31
MAIN RELAY1234BATTERY
FRONT OXYGEN
(A/F) SENSOR

EN(H4DOTC 2.5)-71
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK POWER SUPPLY TO FRONT OXY-
GEN (A/F) SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from front oxygen
(A/F) sensor.
3) Turn the ignition switch to ON.
4) Measure the voltage between front oxygen
(A/F) sensor connector and engine ground.
Connector & terminal
(B262) No. 1 (+) — Engine ground (
−):Is the voltage more than 10 V? Go to step 2.Repair the power
supply line.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
main relay and
front oxygen (A/F)
sensor connector
 Poor contact in
front oxygen (A/F)
sensor connector
 Poor contact in
main relay connec-
tor
2 CHECK GROUND CIRCUIT FOR ECM.
Measure the resistance of harness between
ECM connector and chassis ground.
Connector & terminal
(B134) No. 6 — Chassis ground:
(B134) No. 7 — Chassis ground:Is the resistance less than 5
Ω?Go to step 3.Repair the harness
and connector.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and engine
ground cable
 Poor contact in
ECM connector.
 Poor contact in
coupling connector
3 CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of front oxygen (A/F) sensor
heater current using Subaru Select Monitor or
OBD-II general scan tool.
N
OTE:
 Subaru Select Monitor
For detailed operation procedure, refer to
“READ CURRENT DATA SHOWN ON DIS-
PLAY FOR ENGINE”. <Ref. to EN(H4DOTC
2.5)-27, Subaru Select Monitor.>
 OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Operation Manual.Is the current more than 0.2 A? Repair poor con-
tact connector.
N
OTE:
In this case repair
the following:
 Poor contact in
front oxygen (A/F)
sensor connector
 Poor contact in
ECM connector.Go to step 4.
4 CHECK OUTPUT SIGNAL FROM ECM.
1) Start and idle the engine.
2) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B134) No. 2 (+) — Chassis ground (
−):
(B134) No. 3 (+) — Chassis ground (
−):Is the voltage less than 1 V? Go to step 6.Go to step 5.
5 CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B134) No. 2 (+) — Chassis ground (
−):
(B134) No. 3 (+) — Chassis ground (
−):Does the voltage change by
shaking the harness and con-
nector of ECM while monitor-
ing the value with voltage
meter?Repair the poor
contact in ECM
connector.Go to step 6.

EN(H4DOTC 2.5)-72
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
6 CHECK FRONT OXYGEN (A/F) SENSOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance between front oxy-
gen (A/F) sensor connector terminals.
Te r m i n a l s
No. 1 — No. 2:Is the resistance less than 10
Ω?Repair the harness
and connector.
N
OTE:
In this case repair
the following:
 Open or ground
short circuit in har-
ness between front
oxygen (A/F) sen-
sor and ECM con-
nector
 Poor contact in
front oxygen (A/F)
sensor connector
 Poor contact in
ECM connector.Replace the front
oxygen (A/F) sen-
sor. <Ref. to
FU(H4DOTC 2.5)-
36, Front Oxygen
(A/F) Sensor.> Step Check Yes No

EN(H4DOTC 2.5)-73
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
B: DTC P0032 HO2S HEATER CONTROL CIRCUIT HIGH (BANK 1 SENSOR 1)
DTC DETECTING CONDITION:
Detect as soon as the malfunction occurs.
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-02359
SBF-5
B47 1 2 3 5 4 6
E
E
B21
E236
72
3
26
33
25
ECM
B134
1
3 2
4
B262
34 12
56
123
4
56
78
9
1011 12
1314 15 16
B21 B47 B262
B134
56 7
82 1
94 310
24 22 23 25 11 12 13 14 15
26 27
2816 17
18 19 20 21
33 34 29
32 30 31
MAIN RELAY1234BATTERY
FRONT OXYGEN
(A/F) SENSOR

EN(H4DOTC 2.5)-74
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK OUTPUT SIGNAL FROM ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B134) No. 2 (+) — Chassis ground (
−):
(B134) No. 3 (+) — Chassis ground (
−):Is the voltage more than 8 V? Go to step 3.Go to step 2.
2 CHECK FRONT OXYGEN (A/F) SENSOR
HEATER CURRENT.
1) Turn the ignition switch to OFF.
2) Repair battery short circuit in harness
between ECM and front oxygen (A/F) sensor
connector.
3) Turn the ignition switch to ON.
4) Read the data of front oxygen (A/F) sensor
heater current using Subaru Select Monitor or
OBD-II general scan tool.
N
OTE:
 Subaru Select Monitor
For detailed operation procedure, refer to
“READ CURRENT DATA SHOWN ON DIS-
PLAY FOR ENGINE”. <Ref. to EN(H4DOTC
2.5)-27, Subaru Select Monitor.>
 OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Operation Manual.Is the current more than 2.3 A? Replace the ECM.
<Ref. to
FU(H4DOTC 2.5)-
41, Engine Con-
trol Module
(ECM).>END.
3 CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B134) No. 2 (+) — Chassis ground (
−):
(B134) No. 3 (+) — Chassis ground (
−):Does the voltage change by
shaking the harness and con-
nector of ECM while monitor-
ing the value with voltage
meter?Repair battery
short circuit in har-
ness between
ECM and front
oxygen (A/F) sen-
sor connector.END.

EN(H4DOTC 2.5)-75
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
C: DTC P0037 HO2S HEATER CONTROL CIRCUIT LOW (BANK 1 SENSOR 2)
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-02360
B122 B47 1 2 3 5 4 6
E
E
B21
E23
4
1
B122
34 12
56123
4
56
78
9
1011 12
1314 15 16
: B134
: B135B21
B47 T6
: B136 T6
A6
A7B2
D25
D31
C35
C : B :
D :
4
6
B83A
B
C
B136
B137 B135 B134 A :
: B137
D
56 7
82 1
94 310
24 22 23 25 11 12 13 14 15
26 27
2816 17
18 19 20 21
33 34 29
32 30 31
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
24 22 23 2511 12 13 14 15
26 27
2816 17 18 19
20 21
29 30 31 32 33 34 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
ECM MAIN RELAYBATTERY
REAR OXYGEN
SENSOR
12345678
B18 T52
B18
T5
B18
1234
B83
1
23456
1234
3 1
4
1
2
4
3

EN(H4DOTC 2.5)-76
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK GROUND CIRCUIT FOR ECM.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance of harness
between ECM connector and chassis ground.
Connector & terminal
(B134) No. 6 — Chassis ground:
(B134) No. 7 — Chassis ground:Is the resistance less than 5
Ω?Go to step 2.Repair the har-
ness and connec-
tor.
N
OTE:
In this case repair
the following:
 Open circuit in
harness between
ECM and engine
ground cable
 Poor contact in
ECM connector.
 Poor contact in
coupling connector
2 CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of rear oxygen (A/F) sensor
heater current using Subaru Select Monitor or
OBD-II general scan tool.
NOTE:
 Subaru Select Monitor
For detailed operation procedure, refer to
“READ CURRENT DATA SHOWN ON DIS-
PLAY FOR ENGINE”. <Ref. to EN(H4DOTC
2.5)-27, Subaru Select Monitor.>
 OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Operation Manual.Is the current more than 0.2 A? Repair the connec-
tor.
NOTE:
In this case repair
the following:
 Poor contact in
rear oxygen sen-
sor connector
 Poor contact in
rear oxygen sen-
sor connecting
harness connector
 Poor contact in
ECM connector.Go to step 3.
3 CHECK OUTPUT SIGNAL FROM ECM.
1) Start and idle the engine.
2) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B135) No. 2 (+) — Chassis ground (
−):Is the voltage less than 1 V? Go to step 6.Go to step 4.
4 CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B135) No. 2 (+) — Chassis ground (
−):Does the voltage change by
shaking the harness and con-
nector of ECM while monitor-
ing the value with voltage
meter?Repair the poor
contact in ECM
connector.Go to step 5.
5 CHECK OUTPUT SIGNAL FROM ECM.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from rear oxygen
sensor.
3) Measure the voltage between ECM con-
nector and chassis ground.
Connector & terminal
(B135) No. 2 (+) — Chassis ground (
−):Is the voltage less than 1 V? Replace the ECM.
<Ref. to
FU(H4DOTC 2.5)-
41, Engine Con-
trol Module
(ECM).>Repair battery short
circuit in harness
between ECM and
rear oxygen sensor
connector. After
repair, replace the
ECM. <Ref. to
FU(H4DOTC 2.5)-
41, Engine Con-
trol Module
(ECM).>