2004 INFINITI QX56 ESP

EC-236Revision: August 2007
DTC P0222, P0223 TP SENSOR
2004 QX56
DTC P0222, P0223 TP SENSORPFP:16119
Component DescriptionUBS00H3I
Electric throttle control actuator consists of throttle control motor,
throttle position sensor, etc. The throttle position sensor responds to
the throttle valve movement.
The throttle position sensor has the two sensors. These sensors are
a kind of potentiometers which transform the throttle valve position
into output voltage, and emit the voltage signal to the ECM. In addi-
tion, these sensors detect the opening and closing speed of the
throttle valve and feed the voltage signals to the ECM. The ECM
judges the current opening angle of the throttle valve from these sig-
nals and the ECM controls the throttle control motor to make the
throttle valve opening angle properly in response to driving condi-
tion.
CONSULT-II Reference Value in Data Monitor ModeUBS00H3J
Specification data are reference values.
*: Throttle position sensor 2 signal is converted by ECM internally. Thus, it differs from ECM terminal voltage signal.
On Board Diagnosis LogicUBS00H3K
These self-diagnoses have the one trip detection logic.
FAIL -S AFE M OD E
When the malfunction is detected, ECM enters fail-safe mode and the MIL lights up.
PBIB0145E
MONITOR ITEM CONDITION SPECIFICATION
THRTL SEN1
THRTL SEN2*

Ignition switch: ON
(Engine stopped)

Shift lever: DAccelerator pedal: Fully released More than 0.36V
Accelerator pedal: Fully depressed Less than 4.75V
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0222
0222Throttle position sensor
1 circuit low inputAn excessively low voltage from the TP sensor
1 is sent to ECM.

Harness or connectors
(TP sensor 1 circuit is open or shorted.)
(APP sensor 2 circuit is shorted.)

Electric throttle control actuator
(TP sensor 1)

Accelerator pedal position sensor P0223
0223Throttle position sensor
1 circuit high inputAn excessively high voltage from the TP sen-
sor 1 is sent to ECM.
Engine operation condition in fail-safe mode
The ECM controls the electric throttle control actuator in regulating the throttle opening in order for the idle position to be within +10
degrees.
The ECM regulates the opening speed of the throttle valve to be slower than the normal condition.
So, the acceleration will be poor.

EC-292Revision: August 2007
DTC P0447 EVAP CANISTER VENT CONTROL VALVE
2004 QX56
DTC P0447 EVAP CANISTER VENT CONTROL VALVEPFP:14935
Component DescriptionUBS00H4Z
The EVAP canister vent control valve is located on the EVAP canis-
ter and is used to seal the canister vent.
This solenoid valve responds to signals from the ECM. When the
ECM sends an ON signal, the coil in the solenoid valve is energized.
A plunger will then move to seal the canister vent. The ability to seal
the vent is necessary for the on board diagnosis of other evaporative
emission control system components.
This solenoid valve is used only for diagnosis, and usually remains
opened.
When the vent is closed, under normal purge conditions, the evapo-
rative emission control system is depressurized and allows “EVAP
Control System” diagnosis.
CONSULT-II Reference Value in Data Monitor ModeUBS00H50
Specification data are reference values.
On Board Diagnosis LogicUBS00H51
PBIB1263E
BBIA0443E
MONITOR ITEM CONDITION SPECIFICATION
VENT CONT/V

Ignition switch: ON OFF
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0447
0447EVAP canister vent con-
trol valve circuit openAn improper voltage signal is sent to ECM
through EVAP canister vent control valve.

Harness or connectors
(The valve circuit is open or shorted.)

EVAP canister vent control valve

EC-324Revision: August 2007
DTC P0456 EVAP CONTROL SYSTEM
2004 QX56
DTC P0456 EVAP CONTROL SYSTEMPFP:14950
On Board Diagnosis LogicUBS00H5T
This diagnosis detects very small leaks in the EVAP line between fuel tank and EVAP canister purge volume
control solenoid valve, using the intake manifold vacuum in the same way as conventional EVAP small leak
diagnosis.
If ECM judges a leak which corresponds to a very small leak, the very small leak P0456 will be detected.
If ECM judges a leak equivalent to a small leak, EVAP small leak P0442 will be detected.
If ECM judges there are no leaks, the diagnosis will be OK.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0456
0456Evaporative emission
control system very
small leak (negative
pressure check)

EVAP system has a very small leak.

EVAP system does not operate prop-
erly.

Incorrect fuel tank vacuum relief valve

Incorrect fuel filler cap used

Fuel filler cap remains open or fails to close.

Foreign matter caught in fuel filler cap.

Leak is in line between intake manifold and EVAP
canister purge volume control solenoid valve.

Foreign matter caught in EVAP canister vent con-
trol valve.

EVAP canister or fuel tank leaks

EVAP purge line (pipe and rubber tube) leaks

EVAP purge line rubber tube bent

Loose or disconnected rubber tube

EVAP canister vent control valve and the circuit

EVAP canister purge volume control solenoid
valve and the circuit

Fuel tank temperature sensor

O-ring of EVAP canister vent control valve is miss-
ing or damaged

EVAP canister is saturated with water

EVAP control system pressure sensor

Refueling EVAP vapor cut valve

ORVR system leaks

Fuel level sensor and the circuit

Foreign matter caught in EVAP canister purge vol-
ume control solenoid valve
PBIB1026E

EC-354Revision: August 2007
DTC P1031, P1032, P1051, P1052 A/F SENSOR 1 HEATER
2004 QX56
DTC P1031, P1032, P1051, P1052 A/F SENSOR 1 HEATERPFP:22693
DescriptionUBS00H71
SYSTEM DESCRIPTION
The ECM performs ON/OFF duty control of the A/F sensor 1 heater corresponding to the engine operating
condition to keep the temperature of A/F sensor 1 element at the specified range.
CONSULT-II Reference Value in Data Monitor ModeUBS00H72
Specification data are reference values.
On Board Diagnosis LogicUBS00H73
DTC Confirmation ProcedureUBS00H74
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is between 10.5V and 16V at
idle.
WITH CONSULT-II
1. Turn ignition switch ON and select “DATA MONITOR” mode with
CONSULT-II.
2. Start engine and let it idle for at least 10 seconds.
3. If 1st trip DTC is detected, go to EC-358, "
Diagnostic Procedure"
.
WITH GST
Follow the procedure “WITH CONSULT-II” above.
Sensor Input Signal to ECM ECM function Actuator
Camshaft position sensor (PHASE)
Crankshaft position sensor (POS)Engine speed
Air fuel ratio (A/F) sensor 1
heater controlAir fuel ratio (A/F) sensor 1
heater
Mass air flow sensor Amount of intake air
MONITOR ITEM CONDITION SPECIFICATION
A/F S1 HTR (B1)
A/F S1 HTR (B2)

Engine: After warming up, idle the engine 0 - 100%
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1031
1031
(Bank 1)Air fuel ratio (A/F) sensor
1 heater control circuit
lowThe current amperage in the heated air fuel ratio
(A/F) sensor 1 heater circuit is out of the normal
range.
(An excessively low voltage signal is sent to ECM
through the heated air fuel ratio (A/F) sensor 1
heater.)

Harness or connectors
(The A/F sensor 1 heater circuit is
open or shorted.)

A/F sensor 1 heater P1051
1051
(Bank 2)
P1032
1032
(Bank 1)Air fuel ratio (A/F) sensor
1 heater control circuit
highThe current amperage in the heated air fuel ratio
(A/F) sensor 1 heater circuit is out of the normal
range.
(An excessively high voltage signal is sent to ECM
through the heated air fuel ratio (A/F) sensor 1
heater.)

Harness or connectors
(The A/F sensor 1 heater circuit is
shorted.)

A/F sensor 1 heater P1052
1052
(Bank 2)
SEF 0 58 Y

DTC P1121 ELECTRIC THROTTLE CONTROL ACTUATOR
EC-365
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: August 20072004 QX56
DTC P1121 ELECTRIC THROTTLE CONTROL ACTUATORPFP:16119
Component DescriptionUBS00H7E
Electric throttle control actuator consists of throttle control motor, throttle position sensor, etc.
The throttle control motor is operated by the ECM and it opens and closes the throttle valve.
The throttle position sensor detects the throttle valve position, and the opening and closing speed of the throt-
tle valve and feeds the voltage signals to the ECM. The ECM judges the current opening angle of the throttle
valve from these signals and the ECM controls the throttle control motor to make the throttle valve opening
angle properly in response to driving condition.
On Board Diagnosis LogicUBS00H7F
This self-diagnosis has one trip detection logic.
FAIL-SAFE MODE
When the malfunction is detected, ECM enters fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureUBS00H7G
NOTE:

Perform PROCEDURE FOR MALFUNCTION A AND B first. If the DTC cannot be confirmed, perform
PROCEDURE FOR MALFUNCTION C.

If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait
at least 10 seconds before conducting the next test.
PROCEDURE FOR MALFUNCTION A AND B
With CONSULT-II
1. Turn ignition switch ON and wait at least 1 second.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Shift selector lever to D position and wait at least 2 seconds.
4. Shift selector lever to P position.
5. Turn ignition switch OFF and wait at least 10 seconds.
6. Turn ignition switch ON and wait at least 1 second.
7. Shift selector lever to D position and wait at least 2 seconds.
8. Shift selector lever to P position.
9. Turn ignition switch OFF, wait at least 10 seconds and then turn
ON.
10. If DTC is detected, go to EC-366, "
Diagnostic Procedure" .
With GST
Follow the procedure “With CONSULT-II” above.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1121
11 2 1Electric throttle control
actuatorA)Electric throttle control actuator does not func-
tion properly due to the return spring malfunc-
tion.

Electric throttle control actuator
B)Throttle valve opening angle in fail-safe mode is
not in specified range.
C) ECM detect the throttle valve is stuck open.
Detected items Engine operating condition in fail-safe mode
Malfunction AThe ECM controls the electric throttle actuator by regulating the throttle opening around the idle position.
The engine speed will not rise more than 2,000 rpm.
Malfunction B ECM controls the electric throttle control actuator by regulating the throttle opening to 20 degrees or less.
Malfunction CWhile the vehicle is driving, it slows down gradually by fuel cut. After the vehicle stops, the engine stalls.
The engine can restart in N or P position, and engine speed will not exceed 1,000 rpm or more.
SEF 0 58 Y

DTC P1122 ELECTRIC THROTTLE CONTROL FUNCTION
EC-367
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: August 20072004 QX56
DTC P1122 ELECTRIC THROTTLE CONTROL FUNCTIONPFP:16119
DescriptionUBS00H7I
NOTE:
If DTC P1122 is displayed with DTC P1121 or 1126, first perform the trouble diagnosis for DTC P1121 or
P1126. Refer to EC-365
or EC-373 .
Electric throttle control actuator consists of throttle control motor, throttle position sensor, etc.
The throttle control motor is operated by the ECM and it opens and closes the throttle valve.
The current opening angle of the throttle valve is detected by the throttle position sensor and it provides feed-
back to the ECM to control the throttle control motor to make the throttle valve opening angle properly in
response to driving condition.
On Board Diagnosis LogicUBS00H7J
This self-diagnosis has the one trip detection logic.
FAIL-SAFE MODE
When the malfunction is detected, ECM enters fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureUBS00H7K
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 11V when engine
is running.
WITH CONSULT-II
1. Turn ignition switch ON and wait at least 2 seconds.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Start engine and let it idle for 5 seconds.
4. If DTC is detected, go to EC-369, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1122
11 2 2Electric throttle control
performance problemElectric throttle control function does not oper-
ate properly.

Harness or connectors
(Throttle control motor circuit is open or
shorted)

Electric throttle control actuator
Engine operating condition in fail-safe mode
ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return
spring.
SEF 0 58 Y

EC-378Revision: August 2007
DTC P1128 THROTTLE CONTROL MOTOR
2004 QX56
DTC P1128 THROTTLE CONTROL MOTORPFP:16119
Component DescriptionUBS00H7V
The throttle control motor is operated by the ECM and it opens and closes the throttle valve.
The current opening angle of the throttle valve is detected by the throttle position sensor and it provides feed-
back to the ECM to control the throttle control motor to make the throttle valve opening angle properly in
response to driving condition.
On Board Diagnosis LogicUBS00H7W
This self-diagnosis has the one trip detection logic.
FAIL -S AFE M OD E
When the malfunction is detected, the ECM enters fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureUBS00H7X
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
WITH CONSULT-II
1. Turn ignition switch ON and wait at least 2 seconds.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Start engine and let it idle for 5 seconds.
4. If DTC is detected, go to EC-380, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1128
11 2 8Throttle control motor
circuit shortECM detects short in both circuits between
ECM and throttle control motor.

Harness or connectors
(Throttle control motor circuit is shorted.)

Electric throttle control actuator
(Throttle control motor)
Engine operating condition in fail-safe mode
ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return
spring.
SEF 0 58 Y

DTC P1148, P1168 CLOSED LOOP CONTROL
EC-407
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: August 20072004 QX56
DTC P1148, P1168 CLOSED LOOP CONTROLPFP:22690
On Board Diagnosis LogicUBS00H8K
These self-diagnoses have the one trip detection logic.
DTC P1148 or P1168 is displayed with another DTC for air fuel ratio (A/F) sensor 1.
Perform the trouble diagnosis for the corresponding DTC.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1148
11 4 8
(Bank 1)
Closed loop control
functionThe closed loop control function for bank 1
does not operate even when vehicle is driving
in the specified condition.

Harness or connectors
[The air fuel ratio (A/F) sensor 1 circuit is
open or shorted.]

Air fuel ratio (A/F) sensor 1

Air fuel ratio (A/F) sensor 1 heater P1168
11 6 8
(Bank 2)The closed loop control function for bank 2
does not operate even when vehicle is driving
in the specified condition.