Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual - part 327

GD(H4DOTC)-60

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

5. DIAGNOSTIC METHOD

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

Time Needed for Diagnosis: 24 ms

Malfunction Indicator Light Illumination: Illuminates as soon as a malfunction occurs.
• Normality Judgment
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: 24 ms

Judgment Value

Malfunction Criteria

Threshold Value

Sensor 1 input voltage

≥ 4.858 V

Judgment Value

Malfunction Criteria

Threshold Value

Sensor 1 input voltage

< 4.858 V

GD(H4DOTC)-61

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

AJ:DTC P0125 INSUFFICIENT COOLANT TEMPERATURE FOR CLOSED LOOP 

FUEL CONTROL

1. OUTLINE OF DIAGNOSIS

Detect the malfunction of engine coolant temperature output property.

Judge as NG when the engine coolant temperature does not rise in driving conditions where it should.

2. COMPONENT DESCRIPTION

3. ENABLE CONDITIONS

4. GENERAL DRIVING CYCLE

Perform the diagnosis only once after engine start.

(A)

Resistance value (kΩ)

(B)

Temperature °C (°F)

 

 

 

 

 

 

 

 

(1)

Connector

(2)

Thermistor element

 

 

Secondary Parameters

Enable Conditions

Engine speed

≥ Value from Map

Battery voltage

≥ 10.9 V

Engine coolant temperature at engine starting

< –15 °C (5 °F)

Map

Engine coolant temperature
°C (°F)

–40

(–40)

–30

(–22)

–20

(–4)

–10

(14)

0

(32)

10

(50)

20

(68)

30

(86)

Engine speed
rpm

500

500

500

500

500

500

500

500

Engine coolant temperature
°C (°F)

40

(104)

50

(122)

60

(140)

70

(158)

80

(176)

90

(194)

100

(212)

110

(230)

Engine speed
rpm

500

500

500

500

500

500

500

500

EN-02917

(A)

(2)

(1)

(B)

GD(H4DOTC)-62

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

5. DIAGNOSTIC METHOD

• Abnormality Judgment
Judge as NG if the criteria below are met.

Timer for diagnosis after engine start

64 ms + TWCNT ms (when at 64 ms)

TWCNT is shown in the following table.

Time Needed for Diagnosis: 120 or 300 seconds

Malfunction Indicator Light Illumination:  Illuminates when malfunction occurs in 2 continuous driving cy-

cles.
• Normality Judgment
Judge as OK and clear the NG when the malfunction criteria below are met.

Time Needed for Diagnosis: Less than 1 second

Judgment Value

Malfunction Criteria

Threshold Value

Engine coolant temperature

< –15 °C (5 °F)

Timer for diagnosis after engine start

≥ 299968 ms

 

Vehicle speed km/h (MPH)

0 (0)

8 (5)

16 (9.9)

24 

(14.9)

32 

(19.9)

40 

(24.9)

48 

(29.8)

56 

(34.8)

Lowest engine coolant 
temperature
°C (°F)

–35 (–31)

0

0

0

0

0

0

0

0

–23.5 (–10.3)

0

0

0

0

0

0

0

0

–23.4 (–10.1)

96

96

96

96

96

96

96

96

–15 (5)

96

96

96

96

96

96

96

96

Judgment Value

Malfunction Criteria

Threshold Value

Engine coolant temperature

≥ –15 °C (5 °F)

GD(H4DOTC)-63

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

AK:DTC P0128 COOLANT THERMOSTAT (ENGINE COOLANT TEMPERATURE 

BELOW THERMOSTAT REGULATING TEMPERATURE)

1. OUTLINE OF DIAGNOSIS

Detect malfunctions of the thermostat function.

Judge as NG when any one of the following conditions is established.

• When the actual engine coolant temperature does not reach the maximum temperature necessary to per-

form other OBDII diagnosis and Σ (Estimated engine coolant temperature – actual engine coolant tempera-

ture) exceeded the predetermined value. (Judgment 1)

• When the actual engine coolant temperature does not reach the range within –11°C (–19.8°F) from the

regulated temperature and Σ (Estimated engine coolant temperature – actual engine coolant temperature)

exceeded the predetermined value. (Judgment 2)

• When the difference between the estimated coolant temperature and the actual engine coolant tempera-

ture exceeds the predetermined value, and Σ (Estimated engine coolant temperature – actual engine coolant

temperature) exceeded the predetermined value. (Judgment 3)

2. COMPONENT DESCRIPTION

(1)

Valve

(4)

Piston

(7)

Stop ring

(2)

Spring

(5)

Guide

(8)

Wax element

(3)

Stopper

(6)

Rubber seal

(9)

Jiggle valve

EN-01692

(9)

(2)

(6)

(8)

(7)

(5)

(4)

(3)

(1)

(2)