check engine SUBARU LEGACY 1995 Service Owners Manual

OBD0008C
3. Diagnosis System
A: MALFUNCTION INDICATOR LAMP (MIL)
1. ACTIVATION OF MALFUNCTION INDICATOR LAMP
(MIL)
1) When ignition switch is turned to ON (engine off), the
CHECK ENGINE malfunction indicator lamp (MIL) in the
combination meter illuminates.
NOTE:
If the MIL does not illuminate, perform diagnostics of the
CHECK ENGINE light circuit or the combination meter cir-
cuit. function Indicator Lamp (MIL) [T800]”.>
OBD0053A
2) After starting the engine, the MIL goes out. If it does not,
either the engine or the emission control system is mal-
functioning.
OBD0054A
3) If the diagnosis system senses a misfire which could
damage the catalyzer, the MIL will blink at a cycle of 1 Hz.
OBD0055A
4) When ignition switch is turned to ON (engine off) or to
“START” with the test mode connector connected, the MIL
blinks at a cycle of 3 Hz.
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2-7ON-BOARD DIAGNOSTICS II SYSTEM
3. Diagnosis 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

Function mode Contents Abbreviation Unit of measure
F50 Load data (Freeze frame data) LOADF %
F51 Engine coolant temperature signal (Freeze frame data) TWF °C
F52 Short term fuel trim (Freeze frame data) ALPHF %
F53 Long term fuel trim (Freeze frame data) KBLRF %
F54Intake manifold absolute pressure signal (Freeze frame
data) MANIF kPa
F55 Engine speed signal (Freeze frame data) EREVF rpm
F56 Vehicle speed signal (Freeze frame data) VSPF km/h
FA 0 O N)OFF signal — —
FA 1 O N)OFF signal — —
FA 2 O N)OFF signal — —
FA 3 O N)OFF signal — —
FA 4 O N)OFF signal — —
FB0 Diagnostic trouble code (DTC) INSPECT —
FB1 Diagnostic trouble code (DTC) OBD —
FC0 Clear memory — —
NOTE:
1) Subaru select monitor is also available for monitoring
information other than that used for check and repair of the
vehicle.
2) The maximum values shown for F33, F34, F35 and F36
do not indicate the actual cylinder misfire rate.
36
2-7ON-BOARD DIAGNOSTICS II SYSTEM
3. Diagnosis System

G3M0723

FUNCTION MODE: F00
—MODE DISPLAY—
SPECIFIED DATA:
Data at the left should be indicated.
Probable cause (if outside“specified data”)
1. Communication failure
(No communication method can be confirmed
with power ON.)
(1)Check loose or poor connectors, or
shortcircuit.
(2) Check type of cartridge.
2. Vehicle types cannot be identified (due to
communication failure).Check improper cartridge.
Replace with proper one.
OBD0673

FUNCTION MODE: F01
—BATTERY VOLTAGE (VB)—
CONDITION:
(1) Ignition switch ON
(2) Engine idling after warm-up
SPECIFIED DATA:
(1) 12±1 V
(2) 13±1 V
1. BatteryCheck battery voltage and specific gravity of
electrolyte.
2. Charging system(1)Measure regulating voltage under no loads.
(2) Check generator (as a single unit).
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2-7ON-BOARD DIAGNOSTICS II SYSTEM
3. Diagnosis System

OBD0005B
3. OBD-II GENERAL SCAN TOOL
After performing diagnostics and clearing the memory,
check for any remaining unresolved trouble data:
1) Connect test mode connector at the lower side of the
instrument panel (on the driver’s side), to the side of the
center console box.
OBD0006C
2) Open the cover and connect the OBD-II general scan
tool to its data link connector in the lower portion of the
instrument panel (on the driver’s side), to the lower cover.
CAUTION:
Do not connect the scan tools except for Subaru select
monitor and OBD-II general scan tool.
3) Start the engine.
NOTE:

Ensure the selector lever is placed in the“P”position
before starting. (AT vehicles)

Depress clutch pedal when starting the engine. (MT
vehicles)
4) Using the selector lever or shift lever, turn the“P”posi-
tion switch and the“N”position switch to ON.
5) Depress the brake pedal to turn the brake switch ON.
(AT vehicles)
6) Keep engine speed in the 2,500—3,000 rpm range for
40 seconds.
NOTE:
On models without tachometer, use the Subaru select
monitor or tachometer (Secondary pickup type).
7) Place the selector lever or shift lever in the“D”position
(AT vehicles) or“1st”gear (MT vehicles) and drive the
vehicle at 5 to 10 km/h (3 to 6 MPH).
NOTE:

On AWD vehicles, release the parking brake.

The speed difference between front and rear wheels
may light either the ABS or the ABS/TCS warning light, but
this indicates no malfunctions. When engine control diag-
nosis is finished, perform the ABS or the ABS/TCS memory
clearance procedure of self-diagnosis system. 4-4a [T6C2] or 4-4b [T6C2] or [T9K0].>
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2-7ON-BOARD DIAGNOSTICS II SYSTEM
3. Diagnosis System

When mounting a large power type radio, pay spe-
cial attention to the three items above mentioned.

Incorrect installation of the radio may affect the
operation of the ECM.
8) Before disconnecting the fuel hose, disconnect the fuel
pump connector and crank the engine for more than five
seconds to release pressure in the fuel system. If engine
starts during this operation, run it until it stops.
9) Problems in the electronic-controlled automatic trans-
mission may be caused by failure of the engine, the elec-
tronic control system, the transmission proper, or by a com-
bination of these. These three causes must be distin-
guished clearly when performing diagnostics.
10) Diagnostics should be conducted by rotating with
simple, easy operations and proceeding to complicated,
difficult operations. The most important thing in diagnostics
is to understand the customer’s complaint, and distinguish
between the three causes.
11) In AT vehicles, do not continue the stall for more than
five seconds at a time (from closed throttle, fully open
throttle to stall engine speed).
12) On ABS or ABS/TCS vehicle, when performing driving
test in jacked-up or lifted-up position, sometimes the warn-
ing light may be lit, but this is not a malfunction of the sys-
tem. The reason for this is the speed difference between
the front and rear wheels. After diagnosis of engine control
system, perform the ABS or ABS/TCS memory clearance
procedure of self-diagnosis system. 4-4b [T6C2] or [T9K0].>
C: PRE-INSPECTION
Before performing diagnostics, check the following items
which might affect engine problems:
1. POWER SUPPLY
1) Measure battery voltage and specific gravity of electro-
lyte.
Standard voltage: 12 V
Specific gravity: Above 1.260
2) Check the condition of the main and other fuses, and
harnesses and connectors. Also check for proper ground-
ing.
OBD0091A
2. ENGINE GROUNDING
Make sure the engine grounding terminal is properly con-
nected to the engine.
66
2-7ON-BOARD DIAGNOSTICS II SYSTEM
4. Cautions

3. TRANSMISSION CONTROL MODULE (TCM) I/O
SIGNAL
OBD0093A
Check with ignition switch ON.
ContentConnector
No.Terminal
No.Measuring conditions Voltage (V)
Back-up power supply B56 14 Ignition switch OFF 10—16
Ignition power supplyB54 6
Ignition switch ON (with engine OFF) 10—16
B55 1
Inhibitor switch“P”range switch B56 9Selector lever in“P”range Less than 1
Selector lever in any other than“P”
rangeMore than 8
“N”range switch B56 8Selector lever in“N”range Less than 1
Selector lever in any other than“N”
rangeMore than 8
“R”range switch B56 10Selector lever in“R”range Less than 1
Selector lever in any other than“R”
rangeMore than 6
“D”range switch B54 1Selector lever in“D”range Less than 1
Selector lever in any other than“D”
rangeMore than 6
“3”range switch B54 2Selector lever in“3”range Less than 1
Selector lever in any other than“3”
rangeMore than 6
“2”range switch B54 3Selector lever in“2”range Less than 1
Selector lever in any other than“2”
rangeMore than 6
“1”range switch B54 4Selector lever in“1”range Less than 1
Selector lever in any other than“1”
rangeMore than 6
Brake switch B56 7Brake pedal depressed More than 10.5
Brake pedal released Less than 1
ABS signal B56 5ABS switch ON Less than 1
ABS switch OFF More than 6.5
AT diagnostics signal B55 12Ignition switch ON (with engine OFF) Less than 1
Ignition switch ON (with engine ON) More than 10
Diagnosis switch B56 6Diagnosis connector connected. Less than 1
Diagnosis connector disconnected. More than 6
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2-7ON-BOARD DIAGNOSTICS II SYSTEM
5. Specified Data

7. Basic Diagnostics Procedure
Trouble occurs.
Ask the customer when and how the
trouble occurred using interview
check list.
Start the engine.
Ye sNoInspection using“9. Diagnostics for
Engine Start Failure [T900]”
Malfunction indicator lamp (MIL) illu-
minates.
Ye sNoInspection using“10. General Diag-
nostics Table [T1000]”
Inspection using Subaru select moni-
tor or OBD-II general scan tool.
(Subaru select monitor: MODE FB1)
Trouble code
No trouble code designated.Repair.
See NOTE: *1
designated.
Inspection using“11. Diagnostics
Chart with Trouble Code [T11A0]”.
See NOTE: *2.
Trouble code
designated.

Repair.
Inspection mode
Inspection using Subaru select moni-
tor or OBD-II general scan tool.
(Subaru select monitor: MODE FB0)
No trouble code
Clear memory mode.
designated.
END
NOTE:
*1: If trouble code is not shown on display although the
MIL illuminates, perform diagnostics of the MIL (CHECK
ENGINE LIGHT) circuit or combination meter. Diagnostics for CHECK ENGINE Malfunction Indicator
Lamp (MIL) [T800].”>
*2: Carry out the basic check, only when trouble code
about automatic transmission is shown on display. [T701].>






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2-7ON-BOARD DIAGNOSTICS II SYSTEM
7. Basic Diagnostics Procedure

2. CHECK LIST FOR INTERVIEW
Check the following items when problem occurred.
Customer’s name Engine no.
Date of sale Fuel brand
Date of repair Odometer readingkm
miles
Vin no.
WeatherFineCloudyRainySnowyVarious/Other
Outdoor TemperatureHotWarmCoolCold (approx.°F/°C)
PlaceHighwaySuburbsInner CityUphillDownhill
Rough roadOther
Engine Temp.ColdWarming-upAfter warming-upAny temp.Other
Engine speed
0 2,000 4,000 6,000 8,000 rpm
Driving conditionsNot affected
At startingWhile idlingAt racing
While acceleratingWhile cruising
While deceleratingWhile turning (RH/LH)
Vehicle speed
0 10203040 5060MPH
HeadlightON /OFF
BlowerON /OFF
A/C compressorON /OFF
Cooling fanON /OFF
Front wiperON /OFF
Rear wiperON /OFF
Rear defoggerON /OFF
RadioON /OFF
CD/CassetteON /OFF
Car phoneON /OFF
CB
NOTE: Use copies of this page for interviewing customers.
102
2-7ON-BOARD DIAGNOSTICS II SYSTEM
7. Basic Diagnostics Procedure

Check the following items about the vehicle’s state when
MIL turns on.
a) Other warning lights or indicators turn on.Ye s /No

1Low fuel warning light

2Charge indicator light

3AT diagnostics indicator light

4ABS warning light

5TCS warning light

6Engine oil pressure warning light
b) Fuel level

Lack of gasoline:Ye s /No

Indicator position of fuel gauge:
c) Intentional connecting or disconnecting of harness connectors or spark plug cords:Ye s /No

What:
d) Intentional connecting or disconnecting of hoses:Ye s /No

What:
e) Installing of parts other than genuine partsYe s /No

What:

Where:
f) Occurrence of noiseYe s /No

From where:

What kind:
g) Occurrence of smellYe s /No

From where:

What kind:
h) Intrusion of water into engine compartment or passenger compartmentYe s /No
i) Troubles occurred

1Engine does not start.

2Engine stalls during idling.

3Engine stalls while driving.

4Engine speed decreases.

5Engine speed does not decrease.

6Rough idling

7Poor acceleration

8Back fire

9After fire

10No shift

11Excessive shift shock
NOTE: Use copies of this page for interviewing customers.
103
2-7ON-BOARD DIAGNOSTICS II SYSTEM
7. Basic Diagnostics Procedure