ESP SUBARU LEGACY 1995 Service Owner's Guide

11. Diagnostics Chart with Trouble
Code
A: DIAGNOSTIC TROUBLE CODE (DTC) LIST
DTC
No.Abbreviation
(Subaru select monitor)Item Page
P0100 QA Mass air flow sensor circuit malfunction 135
P0101 QA
—R Mass air flow sensor circuit range/performance problem 141
P0105 P
—S Pressure sensor circuit malfunction 144
P0106 P
—R Pressure sensor circuit range/performance problem 151
P0115 TW Engine coolant temperature sensor circuit malfunction 156
P0120 THV Throttle position sensor circuit malfunction 161
P0121 TH
—R Throttle position sensor circuit range/performance problem 167
P0125 TW
—CL Insufficient coolant temperature for closed loop fuel control 169
P0130 FO2
—V Front oxygen sensor circuit malfunction 171
P0133 FO2
—R Front oxygen sensor circuit slow response 177
P0135 FO2H Front oxygen sensor heater circuit malfunction 180
P0136 RO2
—V Rear oxygen sensor circuit malfunction 185
P0139 RO2
—R Rear oxygen sensor circuit slow response 190
P0141 RO2H Rear oxygen sensor heater circuit malfunction 193
P0170 FUEL Fuel trim malfunction 198
P0201 INJ1 Fuel injector circuit malfunction - #1
203 P0202 INJ2 Fuel injector circuit malfunction - #2
P0203 INJ3 Fuel injector circuit malfunction - #3
P0204 INJ4 Fuel injector circuit malfunction - #4
P0301 MIS
—1 Cylinder 1 misfire detected
210 P0302 MIS
—2 Cylinder 2 misfire detected
P0303 MIS
—3 Cylinder 3 misfire detected
P0304 MIS
—4 Cylinder 4 misfire detected
P0325 KNOCK Knock sensor circuit malfunction 217
P0335 CRANK Crankshaft position sensor circuit malfunction 221
P0340 CAM Camshaft position sensor circuit malfunction 225
P0400 EGR Exhaust gas recirculation flow malfunction 229
P0403 EGRSOL Exhaust gas recirculation circuit malfunction 235
P0420 CAT Catalyst system efficiency below threshold 240
P0441 CPC
—F Evaporative emission control system incorrect purge flow 244
P0443 CPC Evaporative emission control system purge control valve circuit malfunction 248
P0500 VSP Vehicle speed sensor malfunction 253
P0505 ISC Idle control system malfunction 256
P0506 ISC
—L Idle control system RPM lower than expected 262
P0507 ISC
—H Idle control system RPM higher than expected 264
P0600—Serial communication link malfunction 266
P0601 RAM Internal control module memory check sum error 268
P0703 BRK Brake switch input malfunction 271
133
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0142
B: DTC P0100
—MASS AIR FLOW SENSOR CIRCUIT
MALFUNCTION (QA)—
OBD0143A
DESCRIPTION:

The MFI system employs a hot film type air flow sensor.
These mass air flow sensors convert the amount of air
taken into the engine into an electric signal by utilizing the
heat transfer phenomenon between the incoming air and a
heating resistor (hot film) located in the air intake.

The features of these flow sensor types are as follows:
1) High-altitude compensation is made automatically.
2) Quick response
3) These are no moving parts.
4) They are compact.
DTC DETECTING CONDITION:

Immediately at fault recognition
TROUBLE SYMPTOM:

Erroneous idling

Engine stalls.

Poor driving performance
135
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0172
F: DTC P0115
—ENGINE COOLANT TEMPERATURE
SENSOR CIRCUIT MALFUNCTION (TW)—
OBD0173A
DESCRIPTION:
The engine coolant temperature sensor is located on the
engine coolant pipe which is made of aluminum alloy. Its
thermistor changes resistance with respect to temperature.
A engine coolant temperature signal converted into resis-
tance is transmitted to the ECM to control the amount of
fuel injection, ignition timing, purge control solenoid valve,
etc.
DTC DETECTING CONDITION:

Immediately at fault recognition
TROUBLE SYMPTOM:

Hard to start

Erroneous idling

Poor driving performance
156
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0181
G: DTC P0120
—THROTTLE POSITION SENSOR CIRCUIT
MALFUNCTION (THV)—
OBD0182A
DESCRIPTION:

A throttle position sensor is provided with a potentiom-
eter which is interlocked with the throttle valve shaft.

This throttle position sensor sends the ECM a potenti-
ometer output signal corresponding to the opening of the
throttle valve. When the level of this signal exceeds a pre-
determined value, the ECM interprets it as complete clo-
sure of the throttle valve and makes a control most suitable
for the engine operation with the throttle valve fully closed.
For correcting error of this signal, the ECM is provided with
a learning function.

Thus, the ECM precisely controls the air-fuel ratio dur-
ing acceleration and deceleration as well as engine idling.
DTC DETECTING CONDITION:

Immediately at fault recognition
TROUBLE SYMPTOM:

Erroneous idling

Engine stalls.

Poor driving performance
161
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0209
K: DTC P0133
—FRONT OXYGEN SENSOR CIRCUIT SLOW
RESPONSE (FO2
—R)—
DESCRIPTION:
Refer to“J: DTC P0130—FRONT OXYGEN SENSOR
CIRCUIT MALFUNCTION—[T11J0]”.
DTC DETECTING CONDITION:

Two consecutive trips with fault
1.Check DTC P0130 on display.
No
Ye s

Inspect DTC P0130 using“11. Diagnostics Chart
with Trouble Code [T1100]”.

In this case, it is unnecessary to inspect DTC
P0133.
2.Check exhaust system.
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODES. [T3D0] and [T3E0].>

177
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0229
N: DTC P0139
—REAR OXYGEN SENSOR CIRCUIT SLOW
RESPONSE (RO2
—R)—
DESCRIPTION:
Refer to“M: DTC P0136—REAR OXYGEN SENSOR
CIRCUIT MALFUNCTION—[T11M0]”.
DTC DETECTING CONDITION:

Two consecutive trips with fault
190
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0340
AG: DTC P0500
—VEHICLE SPEED SENSOR MALFUNCTION
(VSP)—
DESCRIPTION:

The speedometer system is an electric type; it uses no
speedometer cable and drives the speedometer according
to electric pick-up sensor (vehicle speed sensor 2).
The speed sensor 2 is installed on the transmission. The
speed sensor 2 sends the vehicle speed signal (8 pulses
per one turn of speed sensor driven shaft) to the speed
detection circuit in the speedometer where this signal pulse
wave is regulated.
The regulated pulse signal (4 pulses per one turn of speed
sensor driven shaft) is sent to the speedometer drive cir-
cuit and odometer (trip meter) drive circuit.
The output signal from vehicle speed detection circuit is
also used in ECM, TCM, etc.
B6H0022A
B6H0021A

The speed sensor 2 consists of a magnetic resistance
element, magnet ring, driven shaft, spring, etc.
As the driven key rotates, the magnet turns to change the
magnetic field of the coil.
The coil generates power corresponding to a change in the
magnetic field.
One turn of the driven key in the vehicle speed sensor 2
sends 8 pulses of AC signal to the combination meter.
DTC DETECTING CONDITION:

Immediately at fault recognition
253
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0358
OBD0688A
AH: DTC P0505
—IDLE CONTROL SYSTEM MALFUNCTION
(ISC)—
DESCRIPTION:

Idle air control solenoid valve consists of an air cut valve,
duty control valve, intake air passage and a coolant pas-
sage.

Air cut valve contains a bimetallic substance which
responds to coolant temperature, and a duty control valve
which is operated by a signal sent from ECM.

When engine coolant temperature is low, air cut valve is
fully opened by the action of the bimetallic substance so
that the air flow required for low engine coolant tempera-
tures is maintained.

ECM controls duty control valve to bring the operating
engine speed as close to preset idle speed as possible.
DTC DETECTING CONDITION:

Immediately at fault recognition
TROUBLE SYMPTOM:

Erroneous idling

Engine stalls.

Engine breathing
256
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0605
AV: DTC P0740
—TORQUE CONVERTER CLUTCH SYSTEM
MALFUNCTION (LU
—F)—
DESCRIPTION:
The lock-up engaging and disengaging conditions are set
for each gear shift range, gear position and shift pattern
and correspond to the throttle position and vehicle speed,
and the duty solenoid is electronically controlled by TCM
controls the lock-up clutch. The lock-up clutch engagement
and disengagement are controlled by the lock-up control
valve.
DTC DETECTING CONDITION:

Two consecutive trips with fault
TROUBLE SYMPTOM:

No lock-up occurs. (after engine warm-up)

No shift or excessive tight corner“braking”
289
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code

OBD0501
BK: DTC P1700
—THROTTLE POSITION SENSOR CIRCUIT
MALFUNCTION FOR AUTOMATIC
TRANSMISSION (ATTH)—
DESCRIPTION:

The throttle position sensor provides electrical signals
corresponding to the throttle opening. The throttle opening
and accelerator depression speed are detected by this
throttle position sensor output.

Detects throttle opening and determines shift point, line
pressure and lockup vehicle speed according to engine
load.
SOR CIRCUIT MALFUNCTION—[T11G0]”.>
DTC DETECTING CONDITION:

Two consecutive trips with fault
TROUBLE SYMPTOM:

Shift point too high or too low; engine brake not effected
in“3”range; excessive shift shock; excessive tight corner
“braking”
341
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code