Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual - part 379
GD(H4DOTC)-268
Diagnostic Trouble Code (DTC) Detecting Criteria
GENERAL DESCRIPTION
3. ENABLE CONDITIONS
4. GENERAL DRIVING CYCLE
Perform diagnosis continuously at a constant speed of 20 km/h (12.4 MPH) or more after 0 ms have passed
since the engine started.
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: 10000 ms
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 continuous time while the following conditions are established is more
than the predetermined time.
Time Needed for Diagnosis: Less than 1 second
Secondary Parameters
Enable Conditions
Time needed for all secondary parameters to be in enable conditions
≥ 4096 ms
Battery voltage
≥ 10.9 V
Atmospheric pressure
≥ 75 kPa (563 mmHg, 22.2 inHg)
Rear oxygen sensor sub feedback
Execution
Rear oxygen sensor output voltage – Feedback target voltage
– 0.2 V — 0.1 V
or
Rear oxygen sensor sub feedback compensation coefficient
On Min.
or
Rear oxygen sensor sub feedback compensation coefficient
On Max.
Elapsed time after starting the engine
≥ 0 ms
Engine coolant temperature
≥ –40 °C (–40 °F)
Vehicle speed
≥ 20 km/h (12.4 MPH)
Amount of intake air
≥ 6 g/s (0.21 oz/s)
Load change at 180°CA
< 255 g/rev (8.99 oz/rev)
Front oxygen (A/F) sensor impedance
0 Ω — 50 Ω
Learning value of evaporation gas density
< 1
Total time of operating canister purge
≥ 0 s
Targeted lambda value load compensation coefficient
–1 — 1
Judgment Value
Malfunction Criteria
Threshold Value
λ value
< 0.85
Judgment Value
Malfunction Criteria
Threshold Value
λ value
≥ 0.85