ignition INFINITI QX56 2007 Factory Service Manual

DTC P0112, P0113 IAT SENSOR
EC-201
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DTC P0112, P0113 IAT SENSOR
Component DescriptionINFOID:0000000003531697
The intake air temperature sensor is built-into mass air flow sensor.
The sensor detects intake air temperature and transmits a signal to
the ECM.
The temperature sensing unit uses a thermistor which is sensitive to
the change in temperature. Electrical resistance of the thermistor
decreases in response to the temperature rise.
<Reference data>
*: This data is reference value and is measured between ECM terminal 34 (Intake air
temperature sensor) and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output
voltage. Doing so may result in damage to the ECM's transistor.
Use a ground other than ECM terminals, such as the ground.
On Board Diagnosis LogicINFOID:0000000003531698
DTC Confirmation ProcedureINFOID:0000000003531699
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.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Wait at least 5 seconds.
4. If 1st trip DTC is detected, go to EC-202, "
Diagnosis Procedure".
WITH GST
BBIA0355E
Intake air temperature
°C (°F)Voltage* V Resistance kΩ
25 (77) 3.3 1.800 - 2.200
80 (176) 1.2 0.283 - 0.359
SEF012P
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0112
0112Intake air temperature
sensor circuit low inputAn excessively low voltage from the sensor is
sent to ECM.• Harness or connectors
(The sensor circuit is open or shorted.)
• Intake air temperature sensor P0113
0113Intake air temperature
sensor circuit high inputAn excessively high voltage from the sensor is
sent to ECM.
SEF058Y

EC-202
< SERVICE INFORMATION >
DTC P0112, P0113 IAT SENSOR
Follow the procedure “WITH CONSULT-II” above.
Wiring DiagramINFOID:0000000003531700
Diagnosis ProcedureINFOID:0000000003531701
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
BBWA0879E

DTC P0112, P0113 IAT SENSOR
EC-203
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Refer to EC-143, "Ground Inspection".
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2.CHECK INTAKE AIR TEMPERATURE SENSOR POWER SUPPLY CIRCUIT
1. Disconnect mass air flow sensor (with intake air temperature
sensor) harness connector.
2. Turn ignition switch ON.
3. Check voltage between mass air flow sensor terminal 5 and
ground.
OK or NG
OK >> GO TO 3.
NG >> Repair harness or connectors.
3.CHECK INTAKE AIR TEMPERATURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between mass air flow sensor terminal 6 and ECM terminal 67.
Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
4.CHECK INTAKE AIR TEMPERATURE SENSOR
Refer to EC-204, "
Component Inspection".
OK or NG
OK >> GO TO 5.
NG >> Replace mass air flow sensor (with intake air temperature sensor).
BBIA0354E
BBIA0368E
Voltage: Approximately 5V
PBIB1169E
Continuity should exist.

EC-206
< SERVICE INFORMATION >
DTC P0117, P0118 ECT SENSOR
DTC Confirmation Procedure
INFOID:0000000003531706
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.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Wait at least 5 seconds.
4. If DTC is detected, go to EC-207, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-II” above.
Detected items Engine operating condition in fail-safe mode
Engine coolant temper-
ature sensor circuitEngine coolant temperature will be determined by ECM based on the time after turning ignition switch ON
or START.
CONSULT-II displays the engine coolant temperature decided by ECM.
ConditionEngine coolant temperature decided
(CONSULT-II display)
Just as ignition switch is turned ON or START 40°C (104°F)
More than approx. 4 minutes after ignition ON or
START80°C (176°F)
Except as shown above40 - 80°C (104 - 176°F)
(Depends on the time)
When the fail-safe system for engine coolant temperature sensor is activated, the cooling fan operates while
engine is running.
SEF058Y

DTC P0117, P0118 ECT SENSOR
EC-207
< SERVICE INFORMATION >
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Wiring DiagramINFOID:0000000003531707
Diagnosis ProcedureINFOID:0000000003531708
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
BBWA1676E

EC-208
< SERVICE INFORMATION >
DTC P0117, P0118 ECT SENSOR
Refer to EC-143, "Ground Inspection".
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2.CHECK ECT SENSOR POWER SUPPLY CIRCUIT
1. Disconnect engine coolant temperature (ECT) sensor (1) harness connector.
2. Turn ignition switch ON.
3. Check voltage between ECT sensor (1) terminal 1 and ground
with CONSULT-II or tester.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
3.DETECT MALFUNCTIONING RART
Check the following.
• Harness connector F26, F101
• Harness for open or short between ECM and engine coolant temperature sensor
>> Repair open circuit or short to ground or short to power in harness or connectors.
4.CHECK ECT SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECT sensor terminal 2 and ECM terminal 67.
Refer to Wiring Diagram.
BBIA0354E
1. Engine coolant temperature (ETC)
sensor2. Intake manifold
Voltage: Approximately 5V
BBIA0775E
PBIB0080E
Continuity should exist.

EC-210
< SERVICE INFORMATION >
DTC P0122, P0123 TP SENSOR
DTC P0122, P0123 TP SENSOR
Component DescriptionINFOID:0000000003531711
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 ModeINFOID:0000000003531712
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 LogicINFOID:0000000003531713
These self-diagnoses have the one trip detection logic.
FA I L - S A F E M O D E
When the malfunction is detected, ECM enters fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureINFOID:0000000003531714
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 8V at idle.
WITH CONSULT-II
1. Turn ignition switch ON.
PBIB0145E
MONITOR ITEM CONDITION SPECIFICATION
THRTL SEN 1
THRTL SEN 2*• Ignition switch: ON
(Engine stopped)
• Selector 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
P0122
0122Throttle position sensor
2 circuit low inputAn excessively low voltage from the TP sensor
2 is sent to ECM.• Harness or connectors
(TP sensor 2 circuit is open or shorted.)
(APP sensor 2 circuit is shorted.)
• Electric throttle control actuator
(TP sensor 2)
• Accelerator pedal position sensor
(APP sensor 2) P0123
0123Throttle position sensor
2 circuit high inputAn excessively high voltage from the TP sensor
2 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.

DTC P0122, P0123 TP SENSOR
EC-213
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Diagnosis ProcedureINFOID:0000000003531716
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
Refer to EC-143, "
Ground Inspection" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2.CHECK THROTTLE POSITION SENSOR 2 POWER SUPPLY CIRCUIT-I
TER-
MI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
47 YSensor power supply
(Throttle position sensor)[Ignition switch: ON]Approximately 5V
50 B Throttle position sensor 1[Ignition switch: ON]
• Engine: Stopped
• Selector lever: D
• Accelerator pedal: Fully releasedMore than 0.36V
[Ignition switch: ON]
• Engine: Stopped
• Selector lever: D
• Accelerator pedal: Fully depressedLess than 4.75V
66 RSensor ground
(Throttle position sensor)[Engine is running]
•Warm-up condition
• Idle speedApproximately 0V
69 W Throttle position sensor 2[Ignition switch: ON]
• Engine: Stopped
• Selector lever: D
• Accelerator pedal: Fully releasedLess than 4.75V
[Ignition switch: ON]
• Engine: Stopped
• Selector ever: D
• Accelerator pedal: Fully depressedMore than 0.36V
91 W/RSensor power supply
(APP sensor 2)[Ignition switch: ON]Approximately 5V
BBIA0354E

EC-214
< SERVICE INFORMATION >
DTC P0122, P0123 TP SENSOR
1. Disconnect electric throttle control actuator harness connector.
2. Turn ignition switch ON.
3. Check voltage between electric throttle control actuator terminal
2 and ground with CONSULT-II or tester.
OK or NG
OK >> GO TO 7.
NG >> GO TO 3.
3.CHECK THROTTLE POSITION SENSOR 2 POWER SUPPLY CIRCUIT-II
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between electric throttle control actuator terminal 2 and ECM terminal 47.
Refer to Wiring Diagram.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace open circuit.
4.CHECK THROTTLE POSITION SENSOR 2 POWER SUPPLY CIRCUIT-III
Check harness for short to power and short to ground, between the following terminals.
OK or NG
OK >> GO TO 5.
NG >> Repair short to ground or short to power in harness or connectors.
5.CHECK ACCELERATOR PEDAL POSITION SENSOR
Refer to EC-587, "
Component Inspection" .
OK or NG
OK >> GO TO 11.
NG >> GO TO 6.
6.REPLACE ACCELERATOR PEDAL ASSEMBLY
1. Replace the accelerator pedal assembly.
2. Perform EC-77, "
Accelerator Pedal Released Position Learning" .
3. Perform EC-77, "
Throttle Valve Closed Position Learning" .
4. Perform EC-78, "
Idle Air Volume Learning" .
PBIB1480E
Voltage: Approximately 5V
PBIB2065E
Continuity should exist.
ECM terminal Sensor terminal Reference Wiring Diagram
47 Electric throttle control actuator terminal 2EC-212
91 APP sensor terminal 6EC-583

DTC P0122, P0123 TP SENSOR
EC-215
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>>INSPECTION END
7.CHECK THROTTLE POSITION SENSOR 2 GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between electric throttle control actuator terminal 4 and ECM terminal 66.
Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 8.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
8.CHECK THROTTLE POSITION SENSOR 2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between ECM terminal 69 and electric throttle control actuator terminal 3.
Refer to Wiring Diagram.
2. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 9.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
9.CHECK THROTTLE POSITION SENSOR
Refer to EC-215, "
Component Inspection" .
OK or NG
OK >> GO TO 11.
NG >> GO TO 10.
10.REPLACE ELECTRIC THROTTLE CONTROL ACTUATOR
1. Replace the electric throttle control actuator.
2. Perform EC-77, "
Throttle Valve Closed Position Learning" .
3. Perform EC-78, "
Idle Air Volume Learning" .
>>INSPECTION END
11 .CHECK INTERMITTENT INCIDENT
Refer to EC-138
.
>>INSPECTION END
Component InspectionINFOID:0000000003531717
THROTTLE POSITION SENSOR
1. Reconnect all harness connectors disconnected.
2. Perform EC-77, "
Throttle Valve Closed Position Learning" .
3. Turn ignition switch ON.
4. Set selector lever to D position. Continuity should exist.
Continuity should exist.