Engine control unit SUBARU LEGACY 1995 Service User Guide

D: ABS SEQUENCE CONTROL
1) Under the ABS sequence control, after the hydraulic
unit solenoid valve is driven, the operation of the hydraulic
unit can be checked by means of the brake tester or pres-
sure gauge.
2) ABS sequence control can be started by diagnosis con-
nector or select monitor.
B4M0082C
1. OPERATIONAL GUIDELINES OF THE ABS
SEQUENCE CONTROL WITH DIAGNOSIS
CONNECTOR
1) Connect diagnosis terminals to terminal No. 4 of the
diagnosis connector beside driver’s seat heater unit.
2) Ignition switch is turned to ON.
3) Make sure only the start code (code 11) is shown in
normal condition.
NOTE:
When trouble codes are stored in memory, repair the faulty
parts.
4) Set the speed of all wheels at 10 km/h (6 MPH) or less.
5) Turn ignition switch OFF.
6) Within 0.5 seconds after the ABS and TCS warning
lights go out, depress the brake pedal and hold it immedi-
ately after engine starts.
NOTE:

When the ignition switch is set to on, the brake pedal
must not be depressed.

Engine must operate.

If brake pedal is not depressed within 0.5 seconds after
ABS and TCS warning lights go out, the trouble code mode
comes on.
7) After completion of ABS sequence control, turn ignition
switch OFF.
2. OPERATIONAL GUIDELINES OF THE ABS
SEQUENCE CONTROL WITH SELECT MONITOR
1) Connect select monitor to data link connector beside
driver’s seat heater unit.
2) Engine starts.
3) Put select monitor to TCS mode.
4) put select monitor to FBI mode. Make sure code 11 is
indicated.
NOTE:
When trouble codes are stored in memory, repair the faulty
parts.
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4-4SERVICE PROCEDURE
20. Hydraulic Unit for ABS/TCS System

F: TCS SEQUENCE CONTROL
1) Under the TCS sequence control, after the hydraulic
unit solenoid valve is driven, the operation of the hydraulic
unit can be checked by means of the brake tester or pres-
sure gauge.
2) TCS sequence control can be started by diagnosis con-
nector or select monitor.
B4M0082C
1. OPERATIONAL GUIDELINES OF THE TCS
SEQUENCE CONTROL WITH DIAGNOSIS
CONNECTOR
1) Connect diagnosis terminals to terminal No. 4 of the
diagnosis connector beside driver seat heater unit.
2) Ignition switch is turned to ON.
3) Make sure only the start code (code 11) is shown in
normal condition.
NOTE:
When trouble codes are stored in memory, repair the faulty
parts.
4) Set the speed of all wheels at 10 km/h (6 MPH) or less.
5) Turn ignition switch OFF.
6) Start engine, and within 0.5 seconds after the ABS
warning light and TCS warning light go out, press TCS OFF
switch. Within 1.0 second thereafter, release and press the
switch again. Then, keep the switch pressed.
NOTE:

When the TCS sequence control is set to on, the brake
pedal must not be depressed.

Engine must operate.

When TCS OFF switch is not depressed within 0.5 sec-
onds after ABS and TCS warning lights turn off, the trouble
code mode comes on.
7) After completion of TCS sequence control, turn ignition
switch OFF.
95
4-4SERVICE PROCEDURE
20. Hydraulic Unit for ABS/TCS System

2. OPERATIONAL GUIDELINES OF THE TCS
SEQUENCE CONTROL WITH SELECT MONITOR
1) Connect select monitor to data link connector beside
driver’s seat heater unit.
2) Engine starts.
3) Put select monitor to TCS mode.
4) Put select monitor to FBI mode. Make sure code 11 is
indicated.
NOTE:
When trouble codes are stored in memory, repair the faulty
parts.
B4M0639
5) Press FD2 ENT key.
B4M0624
6) When the message shown in the figure is displayed,
press ENT key.
7) Checked portions will be displayed on select monitor.
B4M0627
8) When TCS sequence control cannot be started (by sys-
tem malfunction, etc.), the message shown in the figure will
be displayed.
NOTE:
Read the trouble codes. Repair faulty parts.
96
4-4SERVICE PROCEDURE
20. Hydraulic Unit for ABS/TCS System

1. Supplemental Restraint System
“Airbag”
Airbag system wiring harness is routed near the instrument
panel, heater unit, blower motor and control unit.
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 instrument panel, heater unit,
blower motor and control unit.
2. Heater Unit
A: REMOVAL AND INSTALLATION
1) Disconnect GND cable from battery.
2) Remove heater hoses (inlet, outlet) in engine compart-
ment.
NOTE:
Drain as much coolant from heater unit as possible, and
plug disconnected hose with cloth.

3) Remove instrument panel.

4) Remove steering support beam.

5) Remove evaporator. (With A/C model)

G4M0554
6) Remove heater unit.
11
4-6SERVICE PROCEDURE
1. Supplemental Restraint System“Airbag”- 2. Heater Unit

1. Supplemental Restraint System
“Airbag”
Airbag system wiring harness is routed near the instrument
panel, heater unit, blower motor and control unit.
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 instrument panel, heater unit,
blower motor and control unit.
2. Heater Unit
A: REMOVAL AND INSTALLATION
1) Disconnect GND cable from battery.
2) Remove heater hoses (inlet, outlet) in engine compart-
ment.
NOTE:
Drain as much coolant from heater unit as possible, and
plug disconnected hose with cloth.

3) Remove instrument panel.

4) Remove steering support beam.

5) Remove evaporator. (With A/C model)

G4M0554
6) Remove heater unit.
11
4-6SERVICE PROCEDURE
1. Supplemental Restraint System“Airbag”- 2. Heater Unit

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