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Toyota Sequoia (2005). Manual - part 130
B17424
Monitor Operation Outline
Running
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
Engine
Air pump
ASV
(Electromagnetic Type)
ASV No.2 (Bank 1)
(Vacuum Type)*
System Air Pressure
ASV No.2 (Bank 2)
(Vacuum Type)*
A B
C
D
E
F
*: ASV No.2 opens alternately per a trip.
–
DIAGNOSTICS
ENGINE
DI–315
509
MONITOR DESCRIPTION
The ECM detects pressure change with the pressure sensor to determine malfunctioning parts in the system,
and stores the DTCs. The ECM measures pressure and/or exhaust pulsation of the system at 6 points, A
to F, when the air injection system is in operation or when not in operation. When the pressure is high, the
ECM determines the that pump operates. When exhaust pulsation is detected, the ECM determines that the
ASV is open. The ECM determines malfunction parts based on the measured value, and stores the DTCs.
Points A and B:
ECM detects pressure changes (decrease), and determines that the ASV No.2 is open.
Points C and F:
ECM detects pressure and exhaust pulsation, and determines the pressure pattern of the system.
Point D:
ECM operates the system, as indicated by the dashed lines, to determine which of the ASV No.2 is malfunc-
tioning only when pressure changes cannot be detected at point A or B.
Point E:
ECM detects exhaust pulsation to determine the condition of the system.
Pressure condition in Secondary Air Injection System (Point C and F)
Pattern 1:
Air Pump
ON
Air Switching Valve and Air Switching Valve No.2
Open
Pressure
1 kPa or more
Pulsation detection
Exhaust gas pulsation detected