1995 SUBARU LEGACY Control unit

B6M0372A
8. REAR GATE SWITCH (WAGON)
NOTE:
The rear gate switch is united with the rear gate latch
assembly.
1) Remove rear gate trim panel.
2) Disconnect rod from rear gate latch assembly.
3) Disconnect rear gate switch (combined with luggage
room light switch) connector and power door lock actuator
connector.
4) Remove bolts which secure power door lock actuator.
5) Remove bolts which secure latch.
6) Remove latch and actuator assembly.
7) Installation is in the reverse order of removal.
B6M0373A
9. SECURITY INDICATOR LIGHT
1) Remove screws which secure meter visor.
2) Remove meter visor from instrument panel while dis-
connecting connectors.
3) Remove security indicator light from meter visor.
4) Installation is in the reverse order of removal.
B6M0682A
10. SECURITY CONTROL MODULE
1) Follow the same preparatory procedures when remov-
ing door lock timer.
2) Remove nut which secures security control module,
and remove security control module from bracket while
pulling right side lower end of instrument panel.
CAUTION:
Be careful not to damage instrument panel while pull-
ing its right side lower end.
3) Disconnect connector from security control module.
4) Installation is in the reverse order of removal.
54
6-2SERVICE PROCEDURE
22. Security System

K: DIAGNOSTICS PROCEDURE FOR KEY
CYLINDER LOCK/UNLOCK SWITCH AND
TAMPER SWITCH SIGNAL
NOTE:
Key cylinder lock switch, key cylinder unlock switch and
tamper switch are combined as a unit.
1. Check key cylinder switch input signal for
security control module.
Not OK
OK
Go to next step on basic diagnostics procedure.

2. Check key cylinder switch.
OK
Not OK
Replace key cylinder switch.
Repair or replace wiring harness between key
cylinder switch and security control module.
B6M0499A
1. CHECK KEY CYLINDER SWITCH INPUT SIGNAL
FOR SECURITY CONTROL MODULE.
1) Remove security control module without disconnecting
connector.
2) Measure voltage between security control module con-
nector and body while turning each key cylinder with igni-
tion key.
Doors (RH and LH), and rear gate (WAGON)
Connector & terminal / Specified voltage:
(B93) No. 2—Body/1V,max. (LOCK position)
/ 10 V, or more (other than
LOCK position)
B6M0447A
(B93) No. 14—Body/1V,max. (UNLOCK position)
/ 10 V, or more (other than
UNLOCK position)


96
6-2DIAGNOSTICS
6. Security System

3. READ DATA LIST

MODE $01
—Current powertrain diagnostic data—
Refers to data denoting the current operating condition of
analog input/output, digital input/output and/or the power-
train system.
A list of the support data and PID (Parameter Identification)
codes are shown in the following table.
PID DataUnit of measure
01 Number of emission-related powertrain trouble codes and MIL status ON/OFF
03 Fuel system control status—
04 Calculated engine load value%
05 Engine coolant temperature°C
06 Short term fuel trim%
07 Long term fuel trim%
0B Intake manifold absolute pressurekPa
0C Engine revolutionrpm
0D Vehicle speedkm/h
0E Ignition timing advance°
10 Air flow rate from mass air flow sensor g/sec
11 Throttle valve opening angle%
13 Check whether oxygen sensor is installed.—
14 Oxygen sensor output voltage and short term fuel trim associated with oxygen sensor—bank 1 V and %
15 Oxygen sensor output voltage and short term fuel trim associated with oxygen sensor—bank 2 V and %
1C On-board diagnosis system—
NOTE:
Refer to OBD-II general scan tool manufacturer’s instruc-
tion manual to access generic OBD-II PIDs (MODE $01).
29
2-7ON-BOARD DIAGNOSTICS II SYSTEM
3. Diagnosis System

MODE $02
—Powertrain freeze frame data—
Refers to data denoting the operating condition when
trouble is sensed by the on-board diagnosis system.
A list of the support data and PID (Parameter Identification)
codes are shown in the following table.
PID DataUnit of measure
02 Trouble code that caused CARB required freeze frame data storage—
03 Fuel system control status—
04 Calculated engine load value%
05 Engine coolant temperature°C
06 Short term fuel trim%
07 Long term fuel trim%
0B Intake manifold absolute pressurekPa
0C Engine revolutionrpm
0D Vehicle speedkm/h
NOTE:
Refer to OBD-II general scan tool manufacturer’s instruc-
tion manual to access freeze frame data (MODE $02).

MODE $03
—Emission-related powertrain diagnostic
trouble codes—
Refers to data denoting emission-related powertrain diag-
nostic trouble codes.
For details concerning diagnostic trouble codes, refer to
the DIAGNOSTIC TROUBLE CODE (DTC) LIST [T11A0].
NOTE:
Refer to OBD-II general scan tool manufacturer’s instruc-
tion manual to access emission-related powertrain diag-
nostic trouble codes (MODE $03).
30
2-7ON-BOARD DIAGNOSTICS II SYSTEM
3. Diagnosis System

2. READ DATA FUNCTION KEY LIST FOR ENGINE
Function mode Contents Abbreviation Unit of measure
F00 ROM ID number YEAR—
F01 Battery voltage VB V
F02 Vehicle speed signal VSP m/h
F03 Vehicle speed signal VSP km/h
F04 Engine speed signal EREV rpm
F05 Engine coolant temperature signal TW°F
F06 Engine coolant temperature signal TW°C
F07 Ignition signal ADVS deg
F08 Mass air flow signal QA V
F09 Load data DATA—
F10 Throttle position signal THV V
F11 Injector pulse width TIM mS
F12 Idle air control signal ISC %
F13 Front oxygen sensor output signal FO2 V
F14 Front oxygen sensor maximum output signal FO2max V
F15 Front oxygen sensor minimum output signal FO2min V
F16 Rear oxygen sensor output signal RO2 V
F17 Rear oxygen sensor maximum output signal RO2max V
F18 Rear oxygen sensor minimum output signal RO2min V
F19 Short term fuel trim ALPHA %
F20 Knock sensor signal RTRD deg
F21 A/F correction (short term trim) by rear oxygen sensor PHOS %
F23 Atmospheric absolute pressure signal (AT vehicles) BARO. P V
F24 Intake manifold absolute pressure signal (AT vehicles) MANI. P V
F25 Long term fuel trim KBLRC %
F28 Long term whole fuel trim K0 %
F29 Front oxygen sensor heater current FO2H A
F30 Rear oxygen sensor heater current RO2H A
F33Maximum value of cylinder #1 misfire times during 200
rotationsMF1 %
F34Maximum value of cylinder #2 misfire times during 200
rotationsMF2 %
F35Maximum value of cylinder #3 misfire times during 200
rotationsMF3 %
F36Maximum value of cylinder #4 misfire times during 200
rotationsMF4 %
F37 Maximum EGR system pressure value (AT vehicles) EGRmax mmHg
F38 Minimum EGR system pressure value (AT vehicles) EGRmin mmHg
F45 Load data LOAD %
F46 Throttle position signal THV %
F47 Mass air flow signal QA g/s
F48 Atmospheric absolute pressure signal BARO. P kPa
F49 Intake manifold absolute pressure signal MANI. P kPa
35
2-7ON-BOARD DIAGNOSTICS II SYSTEM
3. Diagnosis System

4. Cautions
A: SUPPLEMENTAL RESTRAINT SYSTEM
“AIRBAG”
Airbag system wiring harness is routed near the engine
control module (ECM), main relay and fuel pump relay.
CAUTION:

All Airbag system wiring harness and connectors
are colored yellow. Do not use electrical test equip-
ment on these circuit.

Be careful not to damage Airbag system wiring har-
ness when servicing the engine control module (ECM),
transmission control module (TCM), main relay and
fuel pump relay.
B: PRECAUTIONS
1) Never connect the battery in reverse polarity.

The ECM will be destroyed instantly.

The fuel injector and other part will be damaged in just
a few minutes more.
2) Do not disconnect the battery terminals while the
engine is running.

A large counter electromotive force will be generated in
the alternator, and this voltage may damage electronic
parts such as ECM, etc.
3) Before disconnecting the connectors of each sensor
and the ECM, be sure to turn OFF the ignition switch.
4) Before removing ECM from the located position, dis-
connect two cables on battery.

Otherwise, the ECM may be damaged.
5) The connectors to each sensor in the engine compart-
ment and the harness connectors on the engine side and
body side are all designed to be waterproof. However, it is
still necessary to take care not to allow water to get into the
connectors when washing the vehicle, or when servicing
the vehicle on a rainy day.
6) Every MFI-related part is a precision part. Do not drop
them.
7) Observe the following cautions when installing a radio
in MFI equipped models.
CAUTION:

The antenna must be kept as far apart as possible
from the control unit.
(The ECM is located under the steering column, inside
of the instrument panel lower trim panel.)

The antenna feeder must be placed as far apart as
possible from the ECM and MFI harness.

Carefully adjust the antenna for correct matching.
65
2-7ON-BOARD DIAGNOSTICS II SYSTEM
4. Cautions

ContentConnector
No.Terminal
No.Signal (V)
Note Ignition SW
Engine ON (Idling)
ON (Engine OFF)
Knock
sensorSignal B84 30 2.8 2.8—
Shield B84 56 0 0—
AT/MT identification B84 50(AT) 5
(MT) 0(AT) 5
(MT) 0When measuring voltage
between ECM and body.
Back-up power supply B84 42 10—13 13—14 Ignition switch“OFF”:10—13
Control unit power
supplyB8415
10—13 13—14—
16
Ignition
control#1,#2 B84 14 0 1—3.4—
#3,#4 B84 13 0 1—3.4—
Fuel
injector# 1 B84 2 10—13 1—14 Waveform
# 2 B84 1 10—13 1—14 Waveform
# 3 B84 18 10—13 1—14 Waveform
# 4 B84 17 10—13 1—14 Waveform
Idle air
control
solenoid
valveOPEN end B84 12—1—13 Waveform
CLOSE
endB84 11—13—1 Waveform
Fuel pump relay
controlB84 84ON: 0.5, or less
OFF: 10—130.5, or less—
A/C relay control B84 85ON: 0.5, or less
OFF: 10—13ON: 0.5, or less
OFF: 13—14—
Radiator fan relay 1
controlB8477
ON: 0.5, or less
OFF: 10—13ON: 0.5, or less
OFF: 13—14—
88
Radiator fan relay 2
controlB84 61ON: 0.5, or less
OFF: 10—13ON: 0.5, or less
OFF: 13—14With A/C vehicles only
Self-shutoff control B84 86 10—13 13—14—
Malfunction indicator
lampB84 31——Light“ON”: 1, or less
Light“OFF”:10—14
Engine speed output B84 33—0—13, or more Waveform
Torque control signal B84 49 5 5—
Torque control cut
signalB84 36 8 8—
Mass air flow signal for
ATB84 35 0—0.3 0.8—1.2—
Purge control solenoid
valveB84 59ON: 1, or less
OFF: 10—13ON: 1, or less
OFF: 13—14—
Atmospheric pressure
sensorB84 23 3.9—4.1 2.0—2.3—
Pressure sources
switching solenoid
valveB84 58ON: 1, or less
OFF: 10—13ON: 1, or less
OFF: 13—14—
EGR solenoid valve B84 60ON: 1, or less
OFF: 10—13ON: 1, or less
OFF: 13—14—
Front oxygen sensor
heater signalB84 44 0—1.0 0—1.0—
Rear oxygen sensor
heater signalB84 43 0—1.0 0—1.0—
TCS signal B84 34 0—70—7 Waveform
AT diagnosis input
signalB84 48Less than 1)More
than 4Less than 1)More
than 4Waveform
GND (sensors) B84 25 0 0—
69
2-7ON-BOARD DIAGNOSTICS II SYSTEM
5. Specified Data

OBD0283
Y: DTC P0325
—KNOCK SENSOR CIRCUIT MALFUNCTION
(KNOCK)—
OBD0284A
DESCRIPTION:
The knock sensor senses engine knocks and send a volt-
age signal to the ECM depending on the degree of the
knock.
This signal information is used for spark timing learning
control to provide optimal spark timing.
The knock sensor is bolted to the cylinder block at #4 pis-
ton. It senses knocks which can occur in any cylinder. Its
components are a weight, which moves up and down when
it senses vibrations, a piezo element, which produces a
voltage, and a resistor, which senses a broken circuit (all
these are molded into a single unit). When the sensor
senses engine knocks, knocking vibration is conveyed to
the weight. The up or down movement of the weight is
applied to the piezo element as a pressure difference. The
knock sensor will then produce a voltage signal in relation
to the degree of the knock.
DTC DETECTING CONDITION:

Immediately at fault recognition
TROUBLE SYMPTOM:

Poor driving performance

Knocking occurs.
217
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code