Subaru LEGACY 2006 Manual page 551

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Diagnostic Trouble Code (DTC) Detecting Criteria
GENERAL DESCRIPTION
BD:DTC P0400 EXHAUST GAS RECIRCULATION FLOW
1. OUTLINE OF DIAGNOSIS
Detect EGR system malfunction.
Intake manifold pressure (negative pressure) is constant because the throttle valve is fully closed during de-
celeration fuel cut. At this time, when the EGR valve is opened/closed, the intake manifold pressure will
change. EGR System OK/NG is judged by the range of this change.
2. COMPONENT DESCRIPTION
( 1 )
( 4 )
(1) ECM
(2) Detecting circuit
(3) Switching circuit
3. ENABLE CONDITION
Secondary Parameters
After engine starting
Engine coolant temperature
Engine speed
Intake manifold pressure (absolute pressure)
Ambient air temperature
Throttle position
Battery voltage
Atmospheric pressure
Vehicle speed
Fuel shut-off function
Neutral switch
Load (A/C, power steering, lighting, rear
defogger, heater fan and radiator fan)
( 2 )
( 3 )
(4) CPU
(5) EGR valve
Enable Conditions
40 seconds or more
≥ 75°C (167°F)
1200 — 2950 rpm
< 40.0 kPa (300 mmHg, 11.81
inHg)
≥ 5°C (41°F)
< 0.25°
> 10.9 V
≥ 75.0 kPa (563 mmHg, 22.17
inHg)
≥ 53 km/h (33 MPH)
In operation
Over 1 second after changing
from OFF and ON to OFF.
No change for over 5 seconds.
GD(H4SO)-114
( 7 )
( 6 )
( 5 )
EN-02192
(6) Main relay
(7) Battery power supply