Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual - part 334

GD(H4DOTC)-88

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

AW:DTC P014C O2 SENSOR SLOW RESPONSE - RICH TO LEAN (BANK 1 SEN-

SOR 1)

1. OUTLINE OF DIAGNOSIS

Detect the slow response of front oxygen (A/F) sensor.

For diagnosis, detect the trouble by processing the λ waveform in normal driving without forcibly changing

the target air fuel ratio.

2. COMPONENT DESCRIPTION

3. ENABLE CONDITIONS

4. GENERAL DRIVING CYCLE

Perform diagnosis only once in a city driving including normal acceleration and deceleration.

(A)

Electromotive force

(B)

Air fuel ratio

(C)

Rich

(D)

Lean

 

 

 

 

 

 

 

 

 

 

(1)

Exhaust gas

(2)

ZrO

2

 

 

Secondary Parameters

Enable Conditions

Battery voltage

> 10.9 V

Closed loop control with main feedback

Operation

Front oxygen (A/F) sensor impedance

≥ 0 Ω
and
< 50 Ω

Elapsed time after starting the engine

≥ 0 ms

Engine coolant temperature

≥ –40 °C (–40 °F)

Engine speed

≥ 1000 rpm

Amount of intake air

≥ 10 g/s (0.35 oz/s)

Elapsed time after returning from the fuel cut

≥ 3000 ms

Accelerator pedal position

≠ 0%

EN-09361

(C)

(B)

(D)

(A)

(2)

(1)

(1)

GD(H4DOTC)-89

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

5. DIAGNOSTIC METHOD 1

Detect the malfunction by checking “Cumulative value of time when λ changes from lean → rich” in compar-

ison to “Time during which diagnosis is in progress”.

• Abnormality Judgment
Judge as NG when the following conditions are established.

Time Needed for Diagnosis: 90 seconds

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

cles.
• Normality Judgment
Judge as OK and clear the NG if the following conditions are established.

Time Needed for Diagnosis: 90 seconds

(A)

Time during which diagnosis is in 
progress

(B)

Cumulative value of time when λ 
changes from lean → rich

 

 

Judgment Value

Malfunction Criteria

Threshold Value

DTC

(Cumulative value of time when λ changes from lean 

→ rich) / (Time during which diagnosis is in progress)

< 0.39  (Models without SI-DRIVE)
< 0.42  (Models with SI-DRIVE)

P014C

> 0.63  (Models without SI-DRIVE)
> 0.56  (Models with SI-DRIVE)

P014D

Judgment Value

Malfunction Criteria

Threshold Value

DTC

(Cumulative value of time when λ changes from lean 

→ rich) / (Time during which diagnosis is in progress)

≥ 0.39  (Models without SI-DRIVE)

≥ 0.42  (Models with SI-DRIVE)

P014C

≤ 0.63  (Models without SI-DRIVE)

≤ 0.56  (Models with SI-DRIVE)

P014D

EN-09340

time

Rich

Lean

 (Sensor output)

Accumulated time

(B)

(A)

GD(H4DOTC)-90

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

6. DIAGNOSTIC METHOD 2

Detect the malfunction by the cumulative value obtained from the amount of variation in λ change.

• Abnormality Judgment
Judge as NG when the following conditions are established.

Time Needed for Diagnosis: 90 seconds

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

cles.
• Normality Judgment
Judge as OK and clear the NG if the following conditions are established.

Time Needed for Diagnosis: 90 seconds

AX:DTC P014D O2 SENSOR SLOW RESPONSE - LEAN TO RICH (BANK 1 SEN-

SOR 1)

1. OUTLINE OF DIAGNOSIS

NOTE:

For  the  detection  standard,  refer  to  DTC  P014C.  <Ref.  to  GD(H4DOTC)-88,  DTC  P014C  O2  SENSOR

SLOW RESPONSE - RICH TO LEAN (BANK 1 SENSOR 1), Diagnostic Trouble Code (DTC) Detecting Cri-

teria.>

 (Sensor output)

EN-09341

n-2

n

n-1

Judgment Value

Malfunction Criteria

Threshold Value

DTC

Cumulative value obtained from the amount of variation in λ change

Σ |(lambda(n) – lambda(n-1)) – (lambda(n-1) – lambda(n-2))|

< Value from Map

P014C and P014D

Map (Models without SI-DRIVE)

Cumulative value obtained from the amount of variation in λ

Σ |lambda(n) – lambda(n-1)|

0.00

4.00

Cumulative value obtained from the amount of variation in λ change

0.00

4.00

Map (Models with SI-DRIVE)

Cumulative value obtained from the amount of variation in λ

Σ |lambda(n) – lambda(n-1)|

0.00

6.00

Cumulative value obtained from the amount of variation in λ change

0.00

6.50

Judgment Value

Malfunction Criteria

Threshold Value

DTC

Cumulative value obtained from the amount of variation in λ change

Σ |(lambda(n) – lambda(n-1)) – (lambda(n-1) – lambda(n-2))|

≥ Value from Map

P014C and P014D

GD(H4DOTC)-91

Diagnostic Trouble Code (DTC) Detecting Criteria

GENERAL DESCRIPTION

AY:DTC P015A O2 SENSOR DELAYED RESPONSE - RICH TO LEAN (BANK 1 

SENSOR 1)

1. OUTLINE OF DIAGNOSIS

Detect the slow response of front oxygen (A/F) sensor.

For diagnosis, detect the trouble by processing the λ waveform in normal driving without forcibly changing

the target air fuel ratio.

2. COMPONENT DESCRIPTION

(A)

Electromotive force

(B)

Air fuel ratio

(C)

Rich

(D)

Lean

 

 

 

 

 

 

 

 

 

 

(1)

Exhaust gas

(2)

ZrO

2

 

 

EN-09361

(C)

(B)

(D)

(A)

(2)

(1)

(1)