Infiniti Q45 (FY33). Manual — part 188
EGR Function (Close)
SYSTEM DESCRIPTION
Crankshaft position sensor
E
Engine speed
ECM
E
EGRC-sole-
noid valve
Mass air flow sensor
E
Amount of intake air
Engine coolant temperature sensor
E
Engine coolant temperature
Ignition switch
E
Start signal
Vehicle speed sensor
E
Vehicle speed
Throttle position sensor
E
Throttle position
Secondary throttle position sensor
E
Throttle position
This system cuts and controls vacuum applied to the
EGR valve to suit engine operating conditions. This
cut-and-control operation is accomplished through
the ECM and the EGRC-solenoid valve. When the
ECM detects any of the following conditions, current
does not flow through the solenoid valve. This
causes the port vacuum to be discharged into the
atmosphere. The EGR valve remain closed.
I
Low engine coolant temperature
I
Engine starting
I
Engine stopped
I
Engine idling
I
Excessively high engine coolant temperature
I
Mass air flow sensor malfunction
I
Low vehicle speed or high vehicle speed
I
TCS is operating
SEF317U
SEF783K
COMPONENT DESCRIPTION
Exhaust gas recirculation (EGR) valve
The EGR valve controls the amount of exhaust gas routed to the
intake manifold. Vacuum is applied to the EGR valve in response
to throttle valve opening. The vacuum controls the movement of a
taper valve connected to the vacuum diaphragm in the EGR valve.
GI
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EM
LC
FE
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PD
FA
RA
BR
ST
RS
BT
HA
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IDX
TROUBLE DIAGNOSIS FOR DTC P0400
EC-281
SEF383RD
EGRC-solenoid valve
The EGRC-solenoid valve responds to signals from the ECM.
When the ECM sends an ON (ground) signal, the coil in the sole-
noid valve is energized. The signal reaches to the EGR valve.
When the ECM sends an OFF signal, a plunger will then move to
cut the vacuum signal from the intake manifold collector to the EGR
valve.
CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE
Specification data are reference values.
MONITOR ITEM
CONDITION
SPECIFICATION
EGR TEMP SEN
I
Engine: After warming up
Less than 4.5V
EGRC SOL/V
I
Lift up drive wheels
I
Engine: After warming up
I
Air conditioner switch: “OFF”
I
Shift lever: “D”
I
No-load
Idle
OFF (CUT)
Revving engine up from idle to 3,000
rpm
ON (FLOW)
ECM TERMINALS AND REFERENCE VALUE
Specification data are reference values, and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring voltage. Doing so may result in damage to the
ECM’s transistor. Use a ground other than ECM terminals such as the body ground.
TER-
MINAL
NO.
WIRE
COLOR
ITEM
CONDITION
DATA
(DC voltage)
75
W
EGR temperature sensor
Engine is running. (Warmed-up condition)
Idle speed
Less than 4.5V
Engine is running. (Warmed-up condition)
EGR system is operating.
0 - 1.0V
10
L/Y
EGRC-solenoid valve
Engine is running. (Warmed-up condition)
Lift up drive wheels and rev engine up from
idle to 3,000 rpm in “D” position.
0 - 0.7V
Engine is running. (Warmed-up condition)
Idle speed
BATTERY VOLTAGE
(11 - 14V)
SEF073P
ON BOARD DIAGNOSIS LOGIC
If the absence of EGR flow is detected by EGR temperature sen-
sor under the condition that calls for EGR, a low-flow malfunction
is diagnosed.
TROUBLE DIAGNOSIS FOR DTC P0400
EGR Function (Close) (Cont’d)
EC-282
Diagnostic Trouble
Code No.
Malfunction is detected when ...
Check Items
(Possible Cause)
P0400
0302
I
No EGR flow is detected under conditions that call
for EGR.
I
EGR valve stuck closed
I
EGRC-BPT valve
I
Vacuum hose
I
EGRC-solenoid valve
I
EGR passage
I
EGR temperature sensor
I
Exhaust gas leaks
SEF988Z
SEC043C
SEF235Y
DIAGNOSTIC TROUBLE CODE CONFIRMATION
PROCEDURE
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
I
If “DIAGNOSTIC TROUBLE CODE CONFIRMATION PRO-
CEDURE” has been previously conducted, always turn
ignition switch “OFF” and wait at least 5 seconds before
conducting the next test.
I
P0400 will not be displayed in the “SELF-DIAG RESULTS”
mode with CONSULT-II even though the DTC work support
test result is “NG”.
TESTING CONDITION:
For best results, perform at a temperature above 5°C (41°F).
1) Turn ignition switch “ON”
2) Check “COOLAN TEMP/S” in “DATA MONITOR”
mode witch CONSULT-II.
Confirm COOLAN TEMP/S value is within the range
listed below.
COOLANT TEMP/S: Less than 40°C (104°F)
If the value is out of range, park the vehicle in a cool
place and allow the engine temperature to stabilize. Do
not attempt to lower the coolant temperature with a fan
or means other than ambient air. Doing so may produce
an inaccurate diagnostic result.
3) Select “EGR SYSTEM P0400” of “EGR SYSTEM” in
“DTC WORK SUPPORT” mode with CONSULT-II.
4) Touch “START”.
5) Start engine (TCS switch “OFF”) and let it idle. When
the engine coolant temperature reaches 70°C (158°F),
immediately go to the next step.
6) Accelerate vehicle to a speed of 40 km/h (25 MPH)
once and then stop vehicle.
If “COMPLETED” with “OK” appears on CONSULT-II
screen, go to step 9).
If “COMPLETED” does not appear on CONSULT-II
screen, go to the following step.
7) Check the output voltage of “THRTL POS SEN” at
closed throttle position.
8) When the following conditions are met, “TESTING” will
be displayed on the CONSULT-II screen. Maintain the
conditions until “TESTING” changes to “COMPLETED”.
(It will take approximately 30 seconds or more.)
CMPS-RPM (POS): 1,200 - 2,000 rpm
Vehicle speed: 10 km/h (6 MPH) or more
B/FUEL SCHDL: 3.3 - 4.5 msec
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TROUBLE DIAGNOSIS FOR DTC P0400
EGR Function (Close) (Cont’d)
EC-283
SEF396W
THRTL POS SEN: X − (X + 0.53) V
X = Voltage value measured at
step 7)
Selector lever: Suitable position
If “TESTING” is not displayed after 5 minutes, retry
from step 2).
9) Make sure that “OK” is displayed after touching “SELF-
DIAG RESULTS”. If “NG” is displayed, refer to “DIAG-
NOSTIC PROCEDURE”, EC-286.
AEC783
SEF410U
OVERALL FUNCTION CHECK
Use this procedure to check the overall EGR function. During this
check, a 1st trip DTC might not be confirmed.
1) Lift up drive wheels.
Start engine (TCS switch “OFF”) and warm it up to nor-
mal operating temperature.
2) Shift to “D” position.
3) Check the EGR valve lifting when revving engine from
idle up to 3,000 rpm.
EGR valve should lift up and down without sticking.
4)
Check voltage between EGR temperature sensor harness con-
nector terminal
q
1
and ground at idle speed.
Less than 4.5V should exist.
5)
Turn ignition switch “OFF”.
6)
Check harness continuity between EGR temperature sensor
harness connector terminal
q
2
and ECM terminal
129
.
Continuity should exist.
7)
Perform “COMPONENTS INSPECTION”, “EGR temperature
sensor”. Refer to EC-289.
8)
If NG, go to “DIAGNOSTIC PROCEDURE”, EC-286.
SEF109L
SEF642Q
TROUBLE DIAGNOSIS FOR DTC P0400
EGR Function (Close) (Cont’d)
EC-284
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