FUEL SYSTEM -On-Vehicle inspection of MFI Components13-261
VOLUME AIR FLOW SENSORMlWFAAs
/
side
@Harness side connector
I@ Harness sideconnector
Fnnine control module connector
Multiport fuel
The area enclosed with :I: is injection relay
applicable only for Turbo vehicle.
I
@I Component connector (Filter reset circuit)
Engine control module
6FU1537
Intake air amount (Wsec)
162451
OlLO838
OPERATION
l The volume air flow sensor is incorporated
within the air cleaner; it functions to convert the
amount of engine air intake to pulse signals of a
frequency proportional to the amount of engine air intake, and to input those/signals to the en-
gine control module. The engine control module
then, based upon those signals, calculates the
amount of fuel injection, etc.
TROUBLESHOOTING HINTS
HINT 1:
If the engine sometimes stalls, try starting the en-
gine and shaking the volume air flow sensor har-
ness.
If the engine then stalls, incorrect or improper con-
tact of the volume air flow sensor connector is the
probable cause.
Hint 2:
If, when the ignition switch is switched ON (but the
engine is not started), the volume air flow sensor
output frequency is any value other than zero, a
malfunction of the volume air flow sensor or of the
engine control module is the probable cause.
Hint 3:
If idling is possible even though the volume air flow
sensor output frequency is deviated from the
stand-
l The power for the volume air flow sensor is supplied from the
multiport fuel injection relay
to the volume air flow sensor, and is grounded
at the engine control module. The volume air
flow sensor, by intermitting the flow of the
5V
voltage applied from the engine control module,
produces pulse signals.
ard value, the cause is usually a malfunction other
than of the volume air flow sensor. Examples:
(1) The flow of air within the volume air flow sensor
is disturbed. (Air duct disconnection or clogged
air cleaner element)
(2) Incomplete combustion within a cylinder.(Malfunction of spark plugs, ingnition coil, injec-
tors, compression pressure, etc.)
(3) Air is taken into the intake manifold through a
leaking gasket, etc.
(4) Incomplete close contact of the EGR valve seat.
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13-362AUTO-CRUISE CONTROL SYSTEM - Troubleshooting
DIAGNOSTIC DISPLAY PATTERNS AND TROUBLE CODES Code Display patterns (output codes)
No.(use with voltmeter)
11
xJa-.tu
Probable causeCheck chart No.
Abnormal condition of actuator drive systemNo.5
Abnormal condition of auto-cruise vacuum
pump drive system
1212vAbnormal condition of vehicle-speed signal No. 4systemov/
13"12vLow-speed limiter activation (The system is -normal if it can be reset.)
ov
14*12v14Automatic cancellation activated by vehicle -speed reduction. (The system is normal if it
ov can be reset.)
15"12v15Control switch malfunction (when SET and No.2, 3
RESUME switches switched ON simul-
ovtaneously)
16"Cancel switch ON signal input (including inputNo. 6-1, 6-2. 6-3
12v16wirings damage or disconnection, or problemin circuitry within the control unit)
ov
we>
Abnormal condition of auto-cruise control unit-
17"12v17Throttle position sensor malfunctionNo. 11
Closed throttle position switch malfunction
ov
NOTE
1. Codes indicated by the * symbol are displayed, if the conditions are satisfied, even if the system is
normal. In either case, the system is normal if it can be reset. If ther\
e is an automatic cancellation not
intentionally made by the driver, however, excluding cancellations explicitly made by the
cancel
procedure, there may be a temporary malfunction such as poor contact of \
a harness connector even
though the system can be reset, and for that reason it is necessary to c\
heck according to each individual check chart that is applicable.
ON
OFF
-
Display when vehicle speed is less thanapproximately 20 km/h (12 mph), or before
the auto-cruise control system is set
0.5 set
++P5 setDiagnostic trouble codes are displayed when, after cancel-
lation of the auto-cruise control system, the vehicle speed
decreases to less than approximately 20 km/h (12 mph),
and are canceled by turning OFF the battery or canceling
the diagnostic trouble codes. (Refer to
P.13-361.)
cuume type> 03ROlS6
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2.Diagnostic trouble codes are displayed when, after cancel-
lation of the auto-cruise control system, the vehicle speed
decreases to less than approximately 20 km/h (12 mph),
and are erased by switching OFF the ignition switch or the
main switch.
