Subaru Legacy IV (2008 year). Manual — part 176

GD(H4SO)-6

List of Diagnostic Trouble Code (DTC)

GENERAL DESCRIPTION

P0852

Neutral Switch Input Circuit High
(MT Model)

<Ref. to GD(H4SO)-155, DTC P0852 NEUTRAL SWITCH INPUT CIRCUIT
HIGH (MT MODEL), Diagnostic Trouble Code (DTC) Detecting Criteria.>

P1152

O2 Sensor Circuit Range/Perfor-
mance (Low) (Bank1 Sensor1)

<Ref. to GD(H4SO)-156, DTC P1152 O2 SENSOR CIRCUIT RANGE/PER-
FORMANCE (LOW) (BANK1 SENSOR1), Diagnostic Trouble Code (DTC)
Detecting Criteria.>

P1153

O2 Sensor Circuit Range/Perfor-
mance (High) (Bank1 Sensor1)

<Ref. to GD(H4SO)-158, DTC P1153 O2 SENSOR CIRCUIT RANGE/PER-
FORMANCE (HIGH) (BANK1 SENSOR1), Diagnostic Trouble Code (DTC)
Detecting Criteria.>

P1160

Return Spring Failure

<Ref. to GD(H4SO)-160, DTC P1160 RETURN SPRING FAILURE, Diagnostic
Trouble Code (DTC) Detecting Criteria.>

P1400

Exhaust Gas Recirculation Flow

<Ref. to GD(H4SO)-161, DTC P1400 FUEL TANK PRESSURE CONTROL
SOLENOID VALVE CIRCUIT LOW, Diagnostic Trouble Code (DTC) Detecting
Criteria.>

P1420

Fuel Tank Pressure Control Sol. Valve
Circuit High

<Ref. to GD(H4SO)-163, DTC P1420 FUEL TANK PRESSURE CONTROL
SOL. VALVE CIRCUIT HIGH, Diagnostic Trouble Code (DTC) Detecting Crite-
ria.>

P1443

Vent Control Solenoid Valve Function
Problem

<Ref. to GD(H4SO)-165, DTC P1443 VENT CONTROL SOLENOID VALVE
FUNCTION PROBLEM, Diagnostic Trouble Code (DTC) Detecting Criteria.>

P1491

Positive Crankcase Ventilation (Blow-
by) Function Problem

<Ref. to GD(H4SO)-167, DTC P1491 POSITIVE CRANKCASE VENTILATION
(BLOW-BY) FUNCTION PROBLEM, Diagnostic Trouble Code (DTC) Detect-
ing Criteria.>

P1492

EGR Solenoid Valve Signal #1 Circuit
Malfunction (Low Input)

<Ref. to GD(H4SO)-169, DTC P1492 EGR SOLENOID VALVE SIGNAL #1
CIRCUIT MALFUNCTION (LOW INPUT), Diagnostic Trouble Code (DTC)
Detecting Criteria.>

P1493

EGR Solenoid Valve Signal #1 Circuit
Malfunction (High Input)

<Ref. to GD(H4SO)-171, DTC P1493 EGR SOLENOID VALVE SIGNAL #1
CIRCUIT MALFUNCTION (HIGH INPUT), Diagnostic Trouble Code (DTC)
Detecting Criteria.>

P1494

EGR Solenoid Valve Signal #2 Circuit
Malfunction (Low Input)

<Ref. to GD(H4SO)-173, DTC P1494 EGR SOLENOID VALVE SIGNAL #2
CIRCUIT MALFUNCTION (LOW INPUT), Diagnostic Trouble Code (DTC)
Detecting Criteria.>

P1495

EGR Solenoid Valve Signal #2 Circuit
Malfunction (High Input)

<Ref. to GD(H4SO)-173, DTC P1495 EGR SOLENOID VALVE SIGNAL #2
CIRCUIT MALFUNCTION (HIGH INPUT), Diagnostic Trouble Code (DTC)
Detecting Criteria.>

P1496

EGR Solenoid Valve Signal #3 Circuit
Malfunction (Low Input)

<Ref. to GD(H4SO)-173, DTC P1496 EGR SOLENOID VALVE SIGNAL #3
CIRCUIT MALFUNCTION (LOW INPUT), Diagnostic Trouble Code (DTC)
Detecting Criteria.>

P1497

EGR Solenoid Valve Signal #3 Circuit
Malfunction (High Input)

<Ref. to GD(H4SO)-173, DTC P1497 EGR SOLENOID VALVE SIGNAL #3
CIRCUIT MALFUNCTION (HIGH INPUT), Diagnostic Trouble Code (DTC)
Detecting Criteria.>

P1498

EGR Solenoid Valve Signal #4 Circuit
Malfunction (Low Input)

<Ref. to GD(H4SO)-173, DTC P1498 EGR SOLENOID VALVE SIGNAL #4
CIRCUIT MALFUNCTION (LOW INPUT), Diagnostic Trouble Code (DTC)
Detecting Criteria.>

P1499

EGR Solenoid Valve Signal #4 Circuit
Malfunction (High Input)

<Ref. to GD(H4SO)-173, DTC P1499 EGR SOLENOID VALVE SIGNAL #4
CIRCUIT MALFUNCTION (HIGH INPUT), Diagnostic Trouble Code (DTC)
Detecting Criteria.>

P1560

Back-Up Voltage Circuit Malfunction

<Ref. to GD(H4SO)-174, DTC P1560 BACK-UP VOLTAGE CIRCUIT MAL-
FUNCTION, Diagnostic Trouble Code (DTC) Detecting Criteria.>

P1570

Antenna

<Ref. to GD(H4SO)-175, DTC P1570 ANTENNA, Diagnostic Trouble Code
(DTC) Detecting Criteria.>

P1571

Reference Code Incompatibility

<Ref. to GD(H4SO)-175, DTC P1571 REFERENCE CODE INCOMPATIBIL-
ITY, Diagnostic Trouble Code (DTC) Detecting Criteria.>

P1572

IMM Circuit Failure

<Ref. to GD(H4SO)-175, DTC P1572 IMM CIRCUIT FAILURE (EXCEPT
ANTENNA CIRCUIT), Diagnostic Trouble Code (DTC) Detecting Criteria.>

P1574

Key Communication Failure

<Ref. to GD(H4SO)-175, DTC P1574 KEY COMMUNICATION FAILURE,
Diagnostic Trouble Code (DTC) Detecting Criteria.>

DTC

Item

Note

GD(H4SO)-7

List of Diagnostic Trouble Code (DTC)

GENERAL DESCRIPTION

P1576

EGI Control Module EEPROM

<Ref. to GD(H4SO)-175, DTC P1576 EGI CONTROL MODULE EEPROM,
Diagnostic Trouble Code (DTC) Detecting Criteria.>

P1577

IMM Control Module EEPROM

<Ref. to GD(H4SO)-175, DTC P1577 IMM CONTROL MODULE EEPROM,
Diagnostic Trouble Code (DTC) Detecting Criteria.>

P1578

Meter Failure

<Ref. to GD(H4SO)-175, DTC P1578 METER FAILURE, Diagnostic Trouble
Code (DTC) Detecting Criteria.>

P1602

Control Module Programming Error

<Ref. to GD(H4SO)-176, DTC P1602 CONTROL MODULE PROGRAMMING
ERROR, Diagnostic Trouble Code (DTC) Detecting Criteria.>

P2096

Post Catalyst Fuel Trim System Too
Lean (Bank 1)

<Ref. to GD(H4SO)-178, DTC P2096 POST CATALYST FUEL TRIM SYSTEM
TOO LEAN (BANK 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

P2097

Post Catalyst Fuel Trim System Too
Rich (Bank 1)

<Ref. to GD(H4SO)-180, DTC P2097 POST CATALYST FUEL TRIM SYSTEM
TOO RICH (BANK 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

P2101

Throttle Actuator Control Motor Circuit
Range/Performance

<Ref. to GD(H4SO)-182, DTC P2101 THROTTLE ACTUATOR CONTROL
MOTOR CIRCUIT RANGE/PERFORMANCE, Diagnostic Trouble Code (DTC)
Detecting Criteria.>

P2102

Throttle Actuator Control Motor Circuit
Low

<Ref. to GD(H4SO)-183, DTC P2102 THROTTLE ACTUATOR CONTROL
MOTOR CIRCUIT LOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>

P2103

Throttle Actuator Control Motor Circuit
High

<Ref. to GD(H4SO)-184, DTC P2103 THROTTLE ACTUATOR CONTROL
MOTOR CIRCUIT HIGH, Diagnostic Trouble Code (DTC) Detecting Criteria.>

P2109

Throttle/Pedal Position Sensor “A”
Minimum Stop Performance

<Ref. to GD(H4SO)-185, DTC P2109 THROTTLE/PEDAL POSITION SEN-
SOR “A” MINIMUM STOP PERFORMANCE, Diagnostic Trouble Code (DTC)
Detecting Criteria.>

P2122

Throttle/Pedal Position Sensor/
Switch “D” Circuit Low Input

<Ref. to GD(H4SO)-186, DTC P2122 THROTTLE/PEDAL POSITION SEN-
SOR/SWITCH “D” CIRCUIT LOW INPUT, Diagnostic Trouble Code (DTC)
Detecting Criteria.>

P2123

Throttle/Pedal Position Sensor/
Switch “D” Circuit High Input

<Ref. to GD(H4SO)-188, DTC P2123 THROTTLE/PEDAL POSITION SEN-
SOR/SWITCH “D” CIRCUIT HIGH INPUT, Diagnostic Trouble Code (DTC)
Detecting Criteria.>

P2127

Throttle/Pedal Position Sensor/
Switch “E” Circuit Low Input

<Ref. to GD(H4SO)-190, DTC P2127 THROTTLE/PEDAL POSITION SEN-
SOR/SWITCH “E” CIRCUIT LOW INPUT, Diagnostic Trouble Code (DTC)
Detecting Criteria.>

P2128

Throttle/Pedal Position Sensor/
Switch “E” Circuit High Input

<Ref. to GD(H4SO)-192, DTC P2128 THROTTLE/PEDAL POSITION SEN-
SOR/SWITCH “E” CIRCUIT HIGH INPUT, Diagnostic Trouble Code (DTC)
Detecting Criteria.>

P2135

Throttle Position Sensor Circuit
Range/Performance

<Ref. to GD(H4SO)-194, DTC P2135 THROTTLE/PEDAL POSITION SEN-
SOR/SWITCH “A”/“B” VOLTAGE CORRELATION, Diagnostic Trouble Code
(DTC) Detecting Criteria.>

P2138

Accelerator Position Sensor Circuit
Range/Performance

<Ref. to GD(H4SO)-196, DTC P2138 THROTTLE/PEDAL POSITION SEN-
SOR/SWITCH “D”/“E” VOLTAGE CORRELATION, Diagnostic Trouble Code
(DTC) Detecting Criteria.>

P2227

Atmospheric Pressure Sensor Range/
Performance

<Ref. to GD(H4SO)-198, DTC P2227 BAROMETRIC PRESSURE CIRCUIT
RANGE/PERFORMANCE, Diagnostic Trouble Code (DTC) Detecting Crite-
ria.>

P2228

Barometric Pressure Circuit Low

<Ref. to GD(H4SO)-199, DTC P2228 BAROMETRIC PRESSURE CIRCUIT
LOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>

P2229

Barometric Pressure Circuit High

<Ref. to GD(H4SO)-200, DTC P2229 BAROMETRIC PRESSURE CIRCUIT
HIGH, Diagnostic Trouble Code (DTC) Detecting Criteria.>

DTC

Item

Note

GD(H4SO)-8

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

2. Diagnostic Trouble Code (DTC) Detecting Criteria

A: DTC P0026 INTAKE VALVE CONTROL SOLENOID CIRCUIT RANGE/

PERFORMANCE (BANK 1)

1. OUTLINE OF DIAGNOSIS

Judge as NG with either Low NG or High NG.
A variable valve lift diagnosis oil pressure switch is installed for diagnosis. It is possible to determine whether
the intake valve is in high mode (increase the amount of lift) or in low mode (suppressing the amount of lift)
when the variable valve lift diagnosis oil pressure switch is turned ON or OFF.

• Normal

• Low NG

When the variable valve lift diagnosis oil pressure switch remains OFF even though the intake valve tried to
enter high mode (oil switching solenoid valve duty is large), this is judged as a Low NG.

• High NG

When the variable valve lift diagnosis oil pressure switch remains ON even though the intake valve tried to
enter low mode (oil switching solenoid valve duty is small), this is judged as a High NG.

2. COMPONENT DESCRIPTION

The variable valve lift system optimizes the intake valve lift by switching between the low lift cam and the high
lift cam according to the engine speed. The amount of intake valve lift is varied by controlling the oil switching
solenoid valve duty according to signals from the ECM.

Oil switching solenoid valve duty

Intake valve

Variable valve lift diagnosis

oil pressure switch

Large

High mode

ON

Minimum

Low mode

OFF

(A)

Low lift

(B)

High lift

EN-05565

(A)

(B)

GD(H4SO)-9

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

3. ENABLE CONDITION

4. GENERAL DRIVING CYCLE

Perform the diagnosis continuously 6 seconds after engine start while variable valve lift is being controlled

5. DIAGNOSTIC METHOD

• Abnormality Judgement

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

Time Needed for Diagnosis:
Low side: 784 ms
High side: 3000 ms
Malfunction Indicator Light Illumination: Illuminates as soon as a malfunction occurs.

• Normality Judgement

Judge as OK and clear the NG if the continuous time while the following conditions are established is more
than the predetermined time.

Time Needed for Diagnosis:
Low side: 208 ms
High side: 3000 ms

Secondary Parameters

Enable Conditions

Battery voltage

t 10.9 V

After engine starting

t 6000 ms

Engine oil temperature

t 15 °C (59 °F)

Variable valve lift control

Operation

Judgement Value

Malfunction Criteria

Threshold Value

Low

Duty ratio

t 62 %

Variable valve lift diagnosis oil pressure
switch

OFF

High

Duty ratio

< 33 %

Variable valve lift diagnosis oil pressure
switch

ON

Judgement Value

Malfunction Criteria

Threshold Value

Low

Duty ratio

t 62 %

Variable valve lift diagnosis oil pressure
switch

ON

High

Duty ratio

< 33 %

Variable valve lift diagnosis oil pressure
switch

OFF