EC-1
ENGINE
C
D
E
F
G
H
I
J
K
L
M
SECTION EC
A
EC
N
O
P
CONTENTS
ENGINE CONTROL SYSTEM
VQ40DE
BASIC INSPECTION ....................................
6
DIAGNOSIS AND REPAIR WORKFLOW .......... 6
Trouble Diagnosis Introduction .................................6
INSPECTION AND ADJUSTMENT ....................12
Basic Inspection ......................................................12
Idle Speed and Ignition Timing Check ....................16
Procedure After Replacing ECM .............................16
Accelerator Pedal Released Position Learning .......16
Throttle Valve Closed Position Learning .................17
Idle Air Volume Learning .........................................17
FUNCTION DIAGNOSIS ..............................20
ENGINE CONTROL SYSTEM ............................20
System Diagram ......................................................20
Engine Control Component Parts Location .............21
MULTIPORT FUEL INJECTION SYSTEM .........28
System Description .................................................28
ELECTRIC IGNITION SYSTEM .........................31
System Description .................................................31
AIR CONDITIONING CUT CONTROL ...............32
Input/Output Signal Chart ........................................32
System Description .................................................32
AUTOMATIC SPEED CONTROL DEVICE
(ASCD) ...............................................................
33
System Description .................................................33
Component Description ...........................................34
CAN COMMUNICATION ....................................35
System Description .................................................35
COOLING FAN CONTROL ................................36
Description ..............................................................36
EVAPORATIVE EMISSION SYSTEM ...............37
Description ...............................................................37
INTAKE VALVE TIMING CONTROL ................40
Description ...............................................................40
VARIABLE INDUCTION AIR SYSTEM ............41
Description ...............................................................41
Vacuum Hose Drawing ............................................43
ON BOARD DIAGNOSTIC (OBD) SYSTEM ....44
Introduction ..............................................................44
Two Trip Detection Logic .........................................44
Emission-related Diagnostic Information .................44
Malfunction Indicator Lamp (MIL) ............................46
CONSULT-III Function (ENGINE) ...........................48
COMPONENT DIAGNOSIS .........................55
TROUBLE DIAGNOSIS - SPECIFICATION
VALUE ...............................................................
55
Description ...............................................................55
Testing Condition .....................................................55
Inspection Procedure ...............................................55
Diagnosis Procedure ...............................................55
POWER SUPPLY AND GROUND CIRCUIT ....63
Diagnosis Procedure ...............................................63
Ground Inspection ...................................................66
U1000, U1001 CAN COMM CIRCUIT ...............67
Description ...............................................................67
On Board Diagnosis Logic .......................................67
DTC Confirmation Procedure ..................................67
Diagnosis Procedure ...............................................67
P0011, P0021 IVT CONTROL ...........................68
On Board Diagnosis Logic .......................................68
DTC Confirmation Procedure ..................................68
Overall Function Check ...........................................69
Diagnosis Procedure ...............................................69
Component Inspection .............................................70
Revision: September 2009
2010 Xterra GCC
