1997 SUBARU LEGACY heater

10S1
CHECK DTC P0135 ON DISPLAY.
: Does the Subaru select monitor or OBD-II
general scan tool indicate DTC P0141 and
P0135 at the same time?
: Go to next step 1).
: Go to step10S2.
B2M0553A
1) Turn ignition switch to OFF.
2) Disconnect connector from ECM.
3) Measure resistance of harness between ECM connec-
tor and chassis ground.
: Connector & terminal
(B84) No. 42—Chassis ground:
Is the resistance less than 5Ω?
: Repair poor contact in ECM connector.
: Repair harness and connector.
NOTE:
In this case, repair the following:

Open circuit in harness between ECM and coupling con-
nector (B22)

Open circuit in harness between coupling connector
(B22) and engine grounding terminal

Poor contact in rear oxygen sensor connector

Poor contact in rear oxygen sensor connecting harness
connector (B19)

Poor contact in coupling connector (B22)
OBD0145A
10S2CONNECT SUBARU SELECT MONITOR
OR THE OBD-II GENERAL SCAN TOOL,
AND READ DATA.
1) Turn ignition switch to OFF.
2) Connect Subaru Select Monitor or the OBD-II general
scan tool to data link connector.
3) Turn ignition switch to ON and Subaru Select Monitor or
OBD-II general scan tool switch to ON.
4) Start engine.
B2M0498
5) Read data on Subaru Select Monitor or OBD-II general
scan tool.

Subaru Select Monitor
Designate mode using function key.
Function mode: F33

F33: Rear oxygen sensor heater current is indicated.
: Is the value more than 0.2 A in function
mode F33?
: Repair connector.
187
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

11. Diagnostic Chart with Trouble Code
for RHD Vehicles
A: DIAGNOSTIC TROUBLE CODE (DTC) LIST
DTC
No.Abbreviation
(Subaru Select Monitor)Item Page
P0101 QA
—RLOW Mass air flow sensor circuit range/performance problem (low input) 426
P0102 QA
—LOW Mass air flow sensor circuit low input 427
P0103 QA
—HI Mass air flow sensor circuit high input 428
P0106 PS
—R2 Pressure sensor circuit range/performance problem 429
P0107 P
—SLOW Pressure sensor circuit low input 430
P0108 P
—SHI Pressure sensor circuit high input 431
P0116 TW
—LOW Engine coolant temperature sensor circuit low input 432
P0117 TW
—HI Engine coolant temperature sensor circuit high input 433
P0121 TH
—RHI Throttle position sensor circuit range/performance problem (high input) 434
P0122 THV
—LOW Throttle position sensor circuit low input 435
P0123 THV
—HI Throttle position sensor circuit high input 436
P0125 TW
—CL Insufficient coolant temperature for closed loop fuel control 437
P0130 FO2
—V Front oxygen sensor circuit malfunction 438
P0133 FO2
—R Front oxygen sensor circuit slow response 439
P0135 FO2H Front oxygen sensor heater circuit malfunction 440
P0136 RO2
—V Rear oxygen sensor circuit malfunction 441
P0139 RO2
—R Rear oxygen sensor circuit slow response 442
P0141 RO2H Rear oxygen sensor heater circuit malfunction 443
P0170 FUEL Fuel trim malfunction 444
P0181 TNKT
—F Fuel temperature sensor A circuit range/performance problem 445
P0182 TNKT
—LOW Fuel temperature sensor A circuit low input 447
P0183 TNKT
—HI Fuel temperature sensor A circuit high input 450
P0261 INJ1 Fuel injector circuit low input - #1 453
P0262 INJ1
—HI Fuel injector circuit high input - #1 455
P0264 INJ2 Fuel injector circuit low input - #2 453
P0265 INJ2
—HI Fuel injector circuit high input - #2 455
P0267 INJ3 Fuel injector circuit low input - #3 453
P0268 INJ3
—HI Fuel injector circuit high input - #3 455
P0270 INJ4 Fuel injector circuit low input - #4 453
P0271 INJ4
—HI Fuel injector circuit high input - #4 455
P0301 MIS
—1 Cylinder 1 misfire detected 457
P0302 MIS
—2 Cylinder 2 misfire detected 457
P0303 MIS
—3 Cylinder 3 misfire detected 457
P0304 MIS
—4 Cylinder 4 misfire detected 457
P0325 KNOCK Knock sensor circuit malfunction 459
P0335 CRANK Crankshaft position sensor circuit malfunction 460
P0336 CRANK
—R Crankshaft position sensor circuit range/performance problem 461
P0340 CAM Camshaft position sensor circuit malfunction 462
423
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostic Chart with Trouble Code for RHD Vehicles

OBD0212
P: DTC P0135
—FRONT OXYGEN SENSOR HEATER
CIRCUIT MALFUNCTION—
WIRING DIAGRAM:
B2M1151
NOTE:
Check front oxygen sensor heater circuit.

440
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostic Chart with Trouble Code for RHD Vehicles

OBD0232
S: DTC P0141
—REAR OXYGEN SENSOR HEATER
CIRCUIT MALFUNCTION—
WIRING DIAGRAM:
B2M1293
NOTE:
Check rear oxygen sensor heater circuit.

443
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostic Chart with Trouble Code for RHD Vehicles

C: INSPECTION MODE
The on-board diagnosis system is designed to detect prob-
lems while the vehicle is being driven. If a problem is found,
the ABS and TCS warning light will illuminate to inform the
driver of the occurrence of a problem. When the warning
light is on, the ABS/TCS system will be inactive and the
normal braking function will work. It is possible for the most
recent trouble code and history of problem to be stored in
memory until cleared.
B4M0082C
D: TROUBLE CODES
When on-board diagnosis of the ABS/TCS control module
detects a problem, the information will be stored in the EEP
ROM as a trouble code. (Stored codes will stay in memory
until they are cleared.)
1. CALLING UP A TROUBLE CODE
1) Take out diagnosis connector from side of driver’s seat
heater unit.
2) Turn ignition switch OFF.
3) Connect diagnosis connector terminal No. 4 to diagno-
sis terminal.
4) Turn ignition switch ON.
5) TCS warning light is set in the diagnostic mode and
blinks to identify trouble code.
6) After the start code (11) is shown, the trouble codes will
be shown in order of the last information first.
NOTE:
When there are no trouble codes in memory, only the start
code (11) is shown.
B4M0383A
16
4-4bBRAKES
6. Diagnostics Chart for On-board Diagnosis System

C: INSPECTION MODE
Reproduce the condition under which the problem has
occurred as much as possible.
Drive the vehicle at a speed more than 40 km/h (25 MPH)
for at least one minute.
B4M0082D
D: TROUBLE CODES
When on-board diagnosis of the ABS control module
detects a problem, the information (up to a maximum of
three) will be stored in the EEP ROM as a trouble code.
When there are more than three, the most recent three will
be stored. (Stored codes will stay in memory until they are
cleared.)
1. CALLING UP A TROUBLE CODE
1) Take out diagnosis connector from side of driver’s seat
heater unit.
2) Turn ignition switch OFF.
3) Connect diagnosis connector terminal 6 to diagnosis
terminal.
4) Turn ignition switch ON.
5) ABS warning light is set in the diagnostic mode and
blinks to identify trouble code.
6) After the start code (11) is shown, the trouble codes will
be shown in order of the last information first.
These repeat for a maximum of 5 minutes.
NOTE:
When there are no trouble codes in memory, only the start
code (11) is shown.
B4M0232A
12
4-4cBRAKES [ABS 5.3 TYPE]
6. Diagnostics Chart for On-board Diagnosis System

C: INSPECTION MODE
Reproduce the condition under which the problem has
occurred as much as possible.
Drive the vehicle at a speed more than 40 km/h (25 MPH)
for at least one minute.
B4M0082D
D: TROUBLE CODES
When on-board diagnosis of the ABS control module
detects a problem, the information (up to a maximum of
three) will be stored in the EEP ROM as a trouble code.
When there are more than three, the most recent three will
be stored. (Stored codes will stay in memory until they are
cleared.)
1. CALLING UP A TROUBLE CODE
1) Take out diagnosis connector from side of driver’s seat
heater unit.
2) Turn ignition switch OFF.
3) Connect diagnosis connector terminal 6 to diagnosis
terminal.
4) Turn ignition switch ON.
5) ABS warning light is set in the diagnostic mode and
blinks to identify trouble code.
6) After the start code (11) is shown, the trouble codes will
be shown in order of the last information first.
These repeat for a maximum of 5 minutes.
NOTE:
When there are no trouble codes in memory, only the start
code (11) is shown.
B4M0232A
14
4-4dBRAKES [ABS 5.3i TYPE]
6. Diagnostics Chart for On-board Diagnosis System

No. Load
MB-1Fuse holder (Rear power supply & seat
heater)
MB-2 Power window circuit breaker
MB-3Engine control module
Fuel pump relay
Main relay
OBD-II service connector
MB-4 A/C relay holder
MB-5 Headlight alarm relay (with security)
MB-6 Headlight LH
MB-7Daytime running light control module
Diode (Lighting)
Diode (Security)
Lighting switch
MB-8Combination meter
Front fog light switch
Headlight RH
Front fog light relay
MB-9Door lock timer
Headlight alarm relay
Interrupt relay
Radio
Security control module
Security indicator light
Spot light
Room light
Step light
Combination meter
Luggage room light
Trailer connector
Trunk room light
MB-10 A/C relay holder
SBF-6ABS relay box
TCS motor relay
SBF-7 TCS valve relay
ALT-1Combination meter
Daytime running light control module
Diode (TCS)
IG Headlight alarm relay
STCruise control module
Engine control module
Inhibitor switch (AT)
Interrupt relay
Starter interlock relay (MT)
FB-1Front washer motor
Rear washer motor
FB-2Engine control module
Main fan relay 1
FB-3Sub fan relay 2
Sub fan motor
FB-4Engine control module
Fuel pump relay
Ignition coil
Transmission control moduleNo. Load
FB-5 ABS relay box
FB-6Side marker light LH
Side marker light RH
FB-7 Door lock timer
FB-9 Hazard switch
FB-10AT shift lock control module
Key warning switch
Power antenna
FB-11 Radio
FB-12 Front accessory power supply
FB-13Mirror heater
Rear power supply relay
Remote control rearview mirror switch
Security control module
Vanity mirror illumination light
FB-14AT shift lock control module
Combination switch
Front wiper motor
Rear wiper motor
Rear wiper relay
FB-15ABS/TCS control module
Transmission control module
FB-16Rear defogger
Rear defogger condenser
Rear defogger switch
FB-17 Rear defogger switch
FB-18AT shift lock control module
Back-up light switch (MT)
Inhibitor switch (AT)
FB-19 Hazard switch
FB-20A/C switch
Combination meter
Mode control panel
TCS off switch
FB-22Blower motor relay
Check connector
Daytime running light control module
Daytime running light relay
FRESH/RECIRC actuator
Hi-beam relay
Power window and sunroof relay
Seat belt timer
FB-23 Airbag control module
FB-24 Airbag control module
FB-25 Lighting switch
20
6-3WIRING DIAGRAM
6. Wiring Diagram