Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual - part 383
GD(H4DOTC)-284
Diagnostic Trouble Code (DTC) Detecting Criteria
GENERAL DESCRIPTION
FP:DTC P2431 SECONDARY AIR INJECTION SYSTEM AIR FLOW /PRESSURE
SENSOR CIRCUIT RANGE/PERFORMANCE
1. OUTLINE OF DIAGNOSIS
Detect the malfunction of secondary air pressure sensor output property.
Judge as NG when the secondary air pressure sensor output is largely different from the intake manifold
pressure at engine start.
2. ENABLE CONDITIONS
3. GENERAL DRIVING CYCLE
Perform the diagnosis with ignition switch ON.
4. 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: 328 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: 262 ms
Secondary Parameters
Enable Conditions
Engine speed
< 300 rpm
Vehicle speed
< 1 km/h (0.6 MPH)
After secondary air system stops
≥ 2976 ms
Judgment Value
Malfunction Criteria
Threshold Value
|Secondary air pipe pressure – Intake
manifold pressure|
≥ 26.7 kPa (200 mmHg, 7.9 inHg)
|Intake manifold pressure at engine start
– Intake manifold pressure|
< 1.3 kPa (9.99 mmHg, 0.4 inHg)
Judgment Value
Malfunction Criteria
Threshold Value
|Secondary air pipe pressure – Intake
manifold pressure|
< 26.7 kPa (200 mmHg, 7.9 inHg)