Infiniti QX4 (R50). Manual — part 238
10 km/h (6 MPH) when rotating wheels with suitable gear posi-
tion.
4)
If NG, go to “Diagnostic Procedure”, EC-421.
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0500 VEHICLE SPEED SENSOR (VSS)
Overall Function Check (Cont’d)
EC-419
Wiring Diagram
NBEC0247
MEC965C
DTC P0500 VEHICLE SPEED SENSOR (VSS)
Wiring Diagram
EC-420
Diagnostic Procedure
NBEC0248
1
CHECK VEHICLE SPEED SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch “OFF”.
2. Disconnect ECM harness connector and combination meter harness connector.
3. Check harness continuity between ECM terminal 86 and combination meter terminal 13.
Refer to Wiring Diagram.
Continuity should exist.
4. Also check harness for short to power.
OK or NG
OK
©
GO TO 3.
NG
©
GO TO 2.
2
DETECT MALFUNCTIONING PART
Check the following.
I
Harness connectors M32, F23
I
Harness for open or short between ECM and combination meter
©
Repair open circuit or short to ground or short to power in harness or connectors.
3
CHECK SPEEDOMETER FUNCTION
Make sure that speedometer functions properly.
OK or NG
OK
©
GO TO 5.
NG
©
GO TO 4.
4
CHECK SPEEDOMETER CIRCUIT FOR OPEN AND SHORT
Check the following.
I
Harness connectors M70, B50
I
Harness for open or short between combination meter and vehicle speed sensor
I
Harness for open or short between vehicle speed sensor and ECM
OK or NG
OK
©
Check combination meter and vehicle speed sensor. Refer to EL section.
NG
©
Repair open circuit or short to ground or short to power in harness or connectors.
5
CHECK INTERMITTENT INCIDENT
Refer to “TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT”, EC-140.
©
INSPECTION END
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0500 VEHICLE SPEED SENSOR (VSS)
Diagnostic Procedure
EC-421
Description
NBEC0249
SYSTEM DESCRIPTION
NBEC0249S01
Sensor
Input Signal to ECM
ECM func-
tion
Actuator
Crankshaft position sensor (POS)
Engine speed (POS signal)
Idle air
control
IACV-AAC valve
Crankshaft position sensor (REF)
Engine speed (REF signal)
Mass air flow sensor
Amount of intake air
Engine coolant temperature sensor
Engine coolant temperature
Ignition switch
Start signal
Throttle position sensor
Throttle position
Park/neutral position (PNP) switch
Park/neutral position
Air conditioner switch
Air conditioner operation
Power steering oil pressure switch
Power steering load signal
Battery
Battery voltage
Vehicle speed sensor
Vehicle speed
Ambient air temperature switch
Ambient air temperature
Intake air temperature sensor
Intake air temperature
Absolute pressure sensor
Ambient barometic pressure
This system automatically controls engine idle speed to a specified
level. Idle speed is controlled through fine adjustment of the
amount of air which by-passes the throttle valve via IACV-AAC
valve. The IACV-AAC valve changes the opening of the air by-pass
passage to control the amount of auxiliary air. This valve is actu-
ated by a step motor built into the valve, which moves the valve in
the axial direction in steps corresponding to the ECM output sig-
nals. One step of IACV-AAC valve movement causes the respec-
tive opening of the air by-pass passage. (i.e. when the step
advances, the opening is enlarged.) The opening of the valve is
varied to allow for optimum control of the engine idling speed. The
crankshaft position sensor (POS) detects the actual engine speed
and sends a signal to the ECM. The ECM then controls the step
position of the IACV-AAC valve so that engine speed coincides with
the target value memorized in ECM. The target engine speed is the
lowest speed at which the engine can operate steadily. The opti-
mum value stored in the ECM is determined by takig into consid-
eration various engine conditions, such as during warm up,
deceleration, and engine load (air conditioner, power steering and
cooling fan operation).
SEF765P
COMPONENT DESCRIPTION
NBEC0249S02
IACV-AAC Valve
NBEC0249S0201
The IACV-AAC valve is operated by a step motor for centralized
control of auxiliary air supply. This motor has four winding phases
and is actuated by the output signals of ECM which turns ON and
OFF two windings each in seqeunce. Each time the IACV-AAC
valve opens or closes to change tha auxiliary air quantity, the ECM
sends a pulse signal to the step motor. When no change in the
auxiliary air quantity is needed, the ECM does not issue the pulse
signal. A certain voltage signal is issued so that the valve remains
at that particular opening.
DTC P0505 IDLE AIR CONTROL VALVE (IACV) — AUXILIARY AIR CONTROL
(AAC) VALVE
Description
EC-422
Нет комментариевНе стесняйтесь поделиться с нами вашим ценным мнением.
Текст