Contents Wiring diagrams Section: Engine Diagnostic Trouble Code (DTC) Detecting Criteria (H4DO): Diagnosis All sections

DIAGNOSTIC METHOD 2 Subaru Forester SJ

DIAGNOSTIC METHOD 2

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

Scheme 39

Scheme 39: DIAGNOSTIC METHOD 2
  1. Abnormality Judgment

Judge as NG when the following conditions are established.

Malfunction CriteriaThreshold ValueDTC
Cumulative value obtained from the amount of variation in lambda change Sum (lambda(n) - lambda(n-1)) - (lambda(n-1) - lambda(n-2))< Value from MapP014C and P014D

JUDGMENT VALUE

Cumulative value obtained from the amount of variation in lambda Sum lambda(n) - lambda(n-1)0.005.00
Cumulative value obtained from the amount of variation in lambda change0.003.00

MAP SPECIFICATION (CVT MODEL EXCEPT FOR PZEV)

Cumulative value obtained from the amount of variation in lambda Sum lambda(n) - lambda(n-1)0.003.00
Cumulative value obtained from the amount of variation in lambda change0.009.00

MAP SPECIFICATION (MT MODEL EXCEPT FOR PZEV)

Cumulative value obtained from the amount of variation in lambda Sum lambda(n) - lambda(n-1)0.003.50
Cumulative value obtained from the amount of variation in lambda change0.003.50

MAP SPECIFICATION (PZEV CVT MODEL)

Cumulative value obtained from the amount of variation in lambda Sum lambda(n) - lambda(n-1)0.002.004.00
Cumulative value obtained from the amount of variation in lambda change0.007.009.00

MAP SPECIFICATION (PZEV MT MODEL)

Time Needed for Diagnosis: 90 seconds

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

  1. Normality Judgment

Judge as OK and clear the NG if the following conditions are established.

Malfunction CriteriaThreshold ValueDTC
Cumulative value obtained from the amount of variation in lambda change Sum (lambda(n) - lambda(n-1)) - (lambda(n-1) - lambda(n-2))> or = Value from MapP014C and P014D

JUDGMENT VALUE

Time Needed for Diagnosis: 90 seconds

Note. For the detection standard, refer to DTC P014C. < Ref. to DTC P014C O2 SENSOR SLOW RESPONSE - RICH TO LEAN (BANK 1 SENSOR 1) , Diagnostic Trouble Code (DTC) Detecting Criteria. >

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

For diagnosis, detect the trouble by processing the lambda waveform in normal driving without forcibly changing the target air fuel ratio.

Scheme 40

Scheme 40: COMPONENT DESCRIPTION

Detect the malfunction depending on the average value of time necessary for lambda to inverse the air fuel ratio from "Lean --> Rich --> Lean" to "Rich --> Lean --> Rich".

Scheme 41

Scheme 41: DIAGNOSTIC METHOD 1
  1. Abnormality Judgment

Judge as NG when the following conditions are established.

Malfunction CriteriaThreshold ValueDTC
Average value of time necessary for lambda to inverse the air fuel ratio to Lean --> Rich --> Lean> 150 ms (CVT model except for PZEV) > 130 ms (MT model except for PZEV) > 150 ms (PZEV CVT model) > 170 ms (PZEV MT model)P015A
Average value of time necessary for lambda to inverse the air fuel ratio to Rich --> Lean --> Rich> 350 ms (CVT model except for PZEV) > 170 ms (MT model except for PZEV) > 200 ms (PZEV CVT model) > 150 ms (PZEV MT model)P015B

JUDGMENT VALUE

Time Needed for Diagnosis: 50 times of inversion

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

  1. Normality Judgment

Judge as OK and clear the NG if the following conditions are established.

Malfunction CriteriaThreshold ValueDTC
Average value of time necessary for lambda to inverse the air fuel ratio to Lean --> Rich --> Lean< or = 150 ms (CVT model except for PZEV) < or = 130 ms (MT model except for PZEV) < or = 150 ms (PZEV CVT model) < or = 170 ms (PZEV MT model)P015A
Average value of time necessary for lambda to inverse the air fuel ratio to Rich --> Lean --> Rich< or = 350 ms (CVT model except for PZEV) < or = 170 ms (MT model except for PZEV) < or = 200 ms (PZEV CVT model) < or = 150 ms (PZEV MT model)P015B

JUDGMENT VALUE

Time Needed for Diagnosis: 50 times of inversion

Detect the malfunction by calculating the average amplitude of lambda.

Scheme 42

Scheme 42: DIAGNOSTIC METHOD 2
  1. Abnormality Judgment

Judge as NG when the following conditions are established.

Malfunction CriteriaThreshold ValueDTC
Average value for lambda amplitude> 0.07 (CVT model) > 0.1 (MT model)P015A and P015B

JUDGMENT VALUE

Time Needed for Diagnosis: 11250 time(s) x 8 ms

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

  1. Normality Judgment

Judge as OK and clear the NG if the following conditions are established.

Malfunction CriteriaThreshold ValueDTC
Average value for lambda amplitude< or = 0.07 (CVT model) < or = 0.1 (MT model)P015A and P015B

JUDGMENT VALUE

Time Needed for Diagnosis: 11250 time(s) x 8 ms