engine INFINITI QX56 2007 Factory Service Manual

DTC P0031, P0032, P0051, P0052 A/F SENSOR 1 HEATER
EC-163
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
K
L
MA
EC
N
P O
DTC P0031, P0032, P0051, P0052 A/F SENSOR 1 HEATER
DescriptionINFOID:0000000003531656
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 ModeINFOID:0000000003531657
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000003531658
DTC Confirmation ProcedureINFOID:0000000003531659
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-167, "
Diagnosis Procedure".
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 4 - 100%
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0031
0031
(Bank 1)
Air fuel ratio (A/F) sensor
1 heater control circuit lowThe current amperage in the air fuel ratio (A/F) sen-
sor 1 heater circuit is out of the normal range.
(An excessively low voltage signal is sent to ECM
through the 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 P0051
0051
(Bank 2)
P0032
0032
(Bank 1)Air fuel ratio (A/F) sensor
1 heater control circuit
highThe current amperage in the air fuel ratio (A/F) sen-
sor 1 heater circuit is out of the normal range.
(An excessively high voltage signal is sent to ECM
through the 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 P0052
0052
(Bank 2)
SEF058Y

DTC P0031, P0032, P0051, P0052 A/F SENSOR 1 HEATER
EC-165
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
K
L
MA
EC
N
P O
Pulse signal is measured by CONSULT-II.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)TER-
MI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
2 LG/B A/F sensor 1 heater (bank 1)[Engine is running]
•Warm-up condition
• Idle speed
(More than 140 seconds after starting en-
gine)Approximately 2.9 - 8.8V
35 BR/R A/F sensor 1 (bank 1)[Engine is running]
•Warm-up condition
• Engine speed: 2,000 rpmApproximately 1.8V
Output voltage varies with air fuel
ratio.
56 BR/G A/F sensor 1 (bank 1)[Ignition switch: ON]Approximately 2.2V
PBIA8148J

DTC P0031, P0032, P0051, P0052 A/F SENSOR 1 HEATER
EC-167
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
K
L
MA
EC
N
P O
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)
Diagnosis ProcedureINFOID:0000000003531661
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 AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT
1. Disconnect air fuel ratio (A/F) sensor 1 harness connector.
2. Turn ignition switch ON.
TER-
MI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
16 G/L A/F sensor 1 (bank 2)[Engine is running]
•Warm-up condition
• Engine speed: 2,000 rpmApproximately 1.8V
Output voltage varies with air fuel
ratio.
24
43GR/G
GR/GA/F sensor 1 heater (bank 2)[Engine is running]
•Warm-up condition
• Idle speed
(More than 140 seconds after starting en-
gine)Approximately 2.9 - 8.8V
75 L/P A/F sensor 1 (bank 2)[Ignition switch: ON]Approximately 2.2V
PBIA8148J
BBIA0354E
BBIA0376E

EC-170
< SERVICE INFORMATION >
DTC P0037, P0038, P0057, P0058 HO2S2 HEATER
DTC P0037, P0038, P0057, P0058 HO2S2 HEATER
DescriptionINFOID:0000000003531664
SYSTEM DESCRIPTION
The ECM performs ON/OFF control of the heated oxygen sensor 2 heater corresponding to the engine speed,
amount of intake air and engine coolant temperature.
OPERATION
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003531665
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000003531666
DTC Confirmation ProcedureINFOID:0000000003531667
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:
Sensor Input signal to ECM ECM function Actuator
Camshaft position sensor (PHASE)
Crankshaft position sensor (POS)Engine speed
Heated oxygen sensor 2
heater controlHeated oxygen sensor 2 heater
Engine coolant temperature sensor Engine coolant temperature
Mass air flow sensor Amount of intake air
Engine speed rpm Heated oxygen sensor 2 heater
Above 3,600OFF
Below 3,600 rpm after the following conditions are met.
• Engine: After warming up
• Keeping the engine speed between 3,500 and 4,000 rpm for 1
minute and at idle for 1 minute under no loadON
MONITOR ITEM CONDITION SPECIFICATION
HO2S2 HTR (B1)
HO2S2 HTR (B2)• Engine speed: Below 3,600 rpm after the following conditions are met.
- Engine: After warming up
- Keeping the engine speed between 3,500 and 4,000 rpm for 1 minute and
at idle for 1 minute under no loadON
• Engine speed: Above 3,600 rpm OFF
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0037
0037
(Bank 1)
Heated oxygen sensor 2
heater control circuit lowThe current amperage in the heated oxygen sen-
sor 2 heater circuit is out of the normal range.
(An excessively low voltage signal is sent to ECM
through the heated oxygen sensor 2 heater.)• Harness or connectors
(The heated oxygen sensor 2 heater
circuit is open or shorted.)
• Heated oxygen sensor 2 heater P0057
0057
(Bank 2)
P0038
0038
(Bank 1)
Heated oxygen sensor 2
heater control circuit highThe current amperage in the heated oxygen sen-
sor 2 heater circuit is out of the normal range.
(An excessively high voltage signal is sent to ECM
through the heated oxygen sensor 2 heater.)• Harness or connectors
(The heated oxygen sensor 2 heater
circuit is shorted.)
• Heated oxygen sensor 2 heater P0058
0058
(Bank 2)

DTC P0037, P0038, P0057, P0058 HO2S2 HEATER
EC-171
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
K
L
MA
EC
N
P O
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 warm it up to the normal operating tempera-
ture.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Start the engine and keep the engine speed between 3,500 rpm
and 4,000 rpm for at least 1 minute under no load.
5. Let engine idle for 1 minute.
6. If 1st trip DTC is detected, go to EC-175, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-II” above.
SEF174Y

DTC P0037, P0038, P0057, P0058 HO2S2 HEATER
EC-173
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
K
L
MA
EC
N
P O
TER-
MI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
6GRHeated oxygen sensor 2
heater (bank 1)[Engine is running]
• Engine speed: Below 3,600 rpm after the fol-
lowing conditions are met.
- Engine: After warming up
- Keeping the engine speed between 3,500
and 4,000 rpm for 1 minute and at idle for 1
minute under no load0 - 1.0V
[Ignition switch: ON]
• Engine: Stopped
[Engine is running]
• Engine speed: Above 3,600 rpm.BATTERY VOLTAGE
(11 - 14V)
55 RHeated oxygen sensor 2
(bank 1)[Engine is running]
• Revving engine from idle to 3,000 rpm quick-
ly after the following conditions are met.
- Engine: After warming up
- Keeping the engine speed between 3,500
and 4,000 rpm for 1 minute and at idle for 1
minute under no load0 - Approximately 1.0V
78 B/WSensor ground
(Heated oxygen sensor 2) [Engine is running]
•Warm-up condition
• Idle speed Approximately 0V

DTC P0037, P0038, P0057, P0058 HO2S2 HEATER
EC-175
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
K
L
MA
EC
N
P O
Diagnosis ProcedureINFOID:0000000003531669
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 HO2S2 POWER SUPPLY CIRCUIT
1. Disconnect heated oxygen sensor 2 harness connector.
TER-
MI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
25 O/GHeated oxygen sensor 2
heater (bank 2)[Engine is running]
• Engine speed: Below 3,600 rpm after the fol-
lowing conditions are met.
- Engine: After warming up
- Keeping the engine speed between 3,500
and 4,000 rpm for 1 minute and at idle for 1
minute under no load0 - 1.0V
[Ignition switch: ON]
• Engine: Stopped
[Engine is running]
• Engine speed: Above 3,600 rpm.BATTERY VOLTAGE
(11 - 14V)
74 LHeated oxygen sensor 2
(bank 2)[Engine is running]
• Revving engine from idle to 3,000 rpm quick-
ly after the following conditions are met.
- Engine: After warming up
- Keeping the engine speed between 3,500
and 4,000 rpm for 1 minute and at idle for 1
minute under no load0 - Approximately 1.0V
78 B/WSensor ground
(Heated oxygen sensor 2) [Engine is running]
•Warm-up condition
• Idle speed Approximately 0V
BBIA0354E
BBIA0435E

EC-178
< SERVICE INFORMATION >
DTC P0075, P0081 IVT CONTROL SOLENOID VALVE
DTC P0075, P0081 IVT CONTROL SOLENOID VALVE
Component DescriptionINFOID:0000000003531672
Intake valve timing control solenoid valve is activated by ON/OFF
pulse duty (ratio) signals from the ECM.
The intake valve timing control solenoid valve changes the oil
amount and direction of flow through intake valve timing control unit
or stops oil flow.
The longer pulse width advances valve angle.
The shorter pulse width retards valve angle.
When ON and OFF pulse widths become equal, the solenoid valve
stops oil pressure flow to fix the intake valve angle at the control
position.
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003531673
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000003531674
DTC Confirmation ProcedureINFOID:0000000003531675
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. Start engine and let it idle for 5 seconds.
4. If 1st trip DTC is detected, go to EC-182, "
Diagnosis Procedure".
WITH GST
Following the procedure “WITH CONSULT-II” above.
PBIB1842E
MONITOR ITEM CONDITION SPECIFICATION
INT/V SOL (B1)
INT/V SOL (B2)• Engine: After warming up
• Selector lever: P or N
• Air conditioner switch: OFF
•No loadIdle 0% - 2%
2,000 rpm Approx. 25% - 50%
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0075
0075
(Bank 1)
Intake valve timing control
solenoid valve circuitAn improper voltage is sent to the ECM
through intake valve timing control solenoid
valve.• Harness or connectors
(Intake valve timing control solenoid valve
circuit is open or shorted.)
• Intake valve timing control solenoid valve P0081
0081
(Bank 2)
SEF058Y

EC-180
< SERVICE INFORMATION >
DTC P0075, P0081 IVT CONTROL SOLENOID VALVE
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)TER-
MI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
10 WIntake valve timing control
solenoid valve (Bank 1)[Engine is running]
•Warm-up condition
• Idle speedBATTERY VOLTAGE
(11 - 14V)
[Engine is running]
•Warm-up condition
• Engine speed: 2,000rpm7 - 12V
111 W / BECM relay
(Self shut-off)[Engine is running]
[Ignition switch: OFF]
• For a few seconds after turning ignition
switch OFF0 - 1.5V
[Ignition switch: OFF]
• More than a few seconds after turning igni-
tion switch OFFBATTERY VOLTAGE
(11 - 14V)
11 9
120BR
BRPower supply for ECM[Ignition switch: ON]BATTERY VOLTAGE
(11 - 14V)
PBIB1790E

EC-182
< SERVICE INFORMATION >
DTC P0075, P0081 IVT CONTROL SOLENOID VALVE
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)
Diagnosis ProcedureINFOID:0000000003531677
1.CHECK INTAKE VALVE TIMING CONTROL SOLENOID VALVE POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect intake valve timing control solenoid valve harness connector.
3. Turn ignition switch ON.
TER-
MI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
11 L GIntake valve timing control
solenoid valve (Bank 2)[Engine is running]
•Warm-up condition
• Idle speedBATTERY VOLTAGE
(11 - 14V)
[Engine is running]
•Warm-up condition
• Engine speed: 2,000rpm7 - 12V
111 W / BECM relay
(Self shut-off)[Engine is running]
[Ignition switch: OFF]
• For a few seconds after turning ignition
switch OFF0 - 1.5V
[Ignition switch: OFF]
• More than a few seconds after turning igni-
tion switch OFFBATTERY VOLTAGE
(11 - 14V)
11 9
120BR
BRPower supply for ECM[Ignition switch: ON]BATTERY VOLTAGE
(11 - 14V)
PBIB1790E
1. Intake valve timing control position
sensor (bank 2)2. Intake valve timing control solenoid
valve (bank 2)3. Drive belt
4. Radiator hose 5. Intake valve timing control solenoid
valve (bank 1)6. Intake valve timing control position
sensor (bank 1)
BBIA0771E