Self-Diagnosis System; Function Of Self-Diagnosis; Relationship Between Modes And Connectors; U-Check Mode - Subaru SVX 1992 Manual

FUEL INJECTION SYSTEM [M7021 2-7
7. Self-diagnosis System
1 . GENERAL
The self-diagnosis system detects and indicates a fault
in various inputs and outputs of the complex electronic
control. The warning light (CHECK ENGINE light) on the
instrument panel indicates occurrence of a fault or
trouble .
Further, against such a failure or sensors as may disable
the drive, the fail-safe function is provided to ensure the
minimal driveability .
2. FUNCTION OF SELF-DIAGNOSIS
The self-diagnosis function has four modes: U-check
mode, Read memory mode, D-check mode and Clear
memory mode . Two terminals (Read memory and Test
mode) and light (CHECK ENGINE light) are used . The
DIAG . terminals are for mode selection and the light
monitors the type of problem .
Relationship between modes and connectors
DIAG .
terminal
l
/ Diagnosis
connector (Black)
I ~ Select monitor
c I , 1 \ connector _
(Yellow)
1
2
3 4
5 6 7 1
8
1 9 10
I ~1 ~
1 Test mode of MPFI
2 Read memory of MPFI
3 Clear memory of SRS
4 -
5 Test mode of power steering
6 Read memory of power steering
7 Diagnosis of power steering
8 Diagnosis of passive belt
9 Diagnosis of SRS
10 Ground
C2-180
Fig . 33
Mode Engine
Read memory Test mode
terminal terminal
U-check Ignition ON DISCONNECT DISCONNECT
Read memory Ignition ON
CONNECT DISCONNECT
D-check
Ignition ON
DISCONNECT
CONNECT
(engine on)
Clear memory
Ignition ON
CONNECT CONNECT
(engine on)
U-check mode
The U-check is a user-oriented mode in which only the
MPFI components necessary for start-up and drive are
diagnosed . On occurrence of a fault, the warning light
(CHECK ENGINE light) is lighted to indicate to the user
that the dealer's inspection is necessary. The diagnosis
of other parts which do not give significant adverse
effect to start-up and drive are excluded from this mode
in order to avoid unnecessary uneasiness to be taken by
the user .
Read memory mode
This mode is used by the dealer to read past problems
(even when the vehicle's monitor light are off) . It is most
effective in detecting poor contact or loose connections
of connectors, harnesses, etc.
D-check mode
This mode is used bythe dealerto checkthe entire MPFI
system and detect faulty parts .
Clear memory mode
This mode is used by the dealer to clear the trouble
code from the memory after the affected part is re-
paired .
After checking on each mode, reinstall DIAG. terminal
to wire harness with tape .
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