2010 INFINITI QX56 heater

P1148, P1168 CLOSED LOOP CONTROLEC-299
< COMPONENT DIAGNOSIS > [VK56DE]
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P1148, P1168 CLOSED LOOP CONTROL
On Board Diagnosis LogicINFOID:0000000005149341
These self-diagnoses have the on
e 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
function The 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.
Revision: April 20092010 QX56

EC-382
< COMPONENT DIAGNOSIS >[VK56DE]
P2A00, P2A03 A/F SENSOR 1
P2A00, P2A03 A/F SENSOR 1
Component DescriptionINFOID:0000000005149460
The air fuel ratio (A/F) sensor 1 is a planar one-cell limit current sen-
sor. The sensor element of the
A/F sensor 1 is composed an elec-
trode layer, which transports ions. It has a heater in the element.
The sensor is capable of precise measurement = 1, but also in the
lean and rich range. Together with its control electronics, the sensor
outputs a clear, continuous signal throughout a wide range.
The exhaust gas components diffuse through the diffusion layer at
the sensor cell. An electrode layer is applied voltage, and this current
relative oxygen density in lean. Also this current relative hydrocar-
bon density in rich.
Therefore, the A/F sensor 1 is able to indicate air fuel ratio by this
electrode layer of current. In addition, a heater is integrated in the
sensor to ensure the required operating temperature of about 800° C
(1,472° F).
On Board Diagn osis LogicINFOID:0000000005149461
To judge the malfunction, the A/F signal computed by ECM from the A/F sensor 1 signal is monitored not to be
shifted to LEAN side or RICH side.
DTC Confirmation ProcedureINFOID:0000000005149462
NOTE:
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure
before conducting the next step.
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 11 V at idle.
WITH CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Turn ignition switch ON and select “SELF-LEARNING CONT” in “WORK SUPPORT” mode with CON-
SULT-III.
4. Clear the self-learning coef ficient by touching “CLEAR”.
PBIB3353E
PBIB3354E
DTC No. Trouble diagnosis name DTC detecting conditionPossible Cause
P2A00
2A00
(Bank 1) Air fuel ratio (A/F) sensor 1
circuit range/performance • The output voltage computed by ECM from the
A/F sensor 1 signal is shifted to the lean side for
a specified period.
• The A/F signal computed by ECM from the A/F
sensor 1 signal is shifted to the rich side for a
specified period. • A/F sensor 1
• A/F sensor 1 heater
• Fuel pressure
• Fuel injector
• Intake air leaks
P2A03
2A03
(Bank 2)
Revision: April 20092010 QX56

EC-386
< COMPONENT DIAGNOSIS >[VK56DE]
P2A00, P2A03 A/F SENSOR 1
5. Also check harness for 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 A/F SENSOR 1 HEATER
Refer to EC-97, "
Component Inspection".
OK or NG
OK >> GO TO 10.
NG >> GO TO 11.
10.CHECK INTERMITTENT INCIDENT
Perform GI-35, "
How to Check Terminal" and GI-38, "Intermittent Incident".
OK or NG
OK >> GO TO 11.
NG >> Repair or replace.
11 .REPLACE AIR FUEL RATIO (A/F) SENSOR 1
Replace malfunctioning air fuel ratio (A/F) sensor 1.
CAUTION:
• Discard any A/F sensor which has been dropped from a height of more than 0.5 m (1.6 ft) onto a hard surface such as a concrete floor; use a new one.
• Before installing new A/F sensor, clean exhau st system threads using Oxygen Sensor Thread
Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.
>> GO TO 12.
12.CONFIRM A/F ADJUSTMENT DATA
1. Turn ignition switch OFF and then ON.
2. Select “A/F ADJ-B1” and “” in “D ATA MONITOR” mode with CONSULT-III.
3. Make sure that “0.000” is displayed on CONSULT-III screen.
OK or NG
OK >> INSPECTION END
NG >> GO TO 13.
13.CLEAR THE SELF-LEARNING DATA
With CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Select “SELF-LEARNING CONT” in “WORK SUPPORT” mode with CONSULT-III.
3. Clear the self-learning control coefficient by touching “CLEAR”.
Without CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF.
Bank 1 Bank 2
A/F sensor 1 terminal ECM terminal A/F sensor 1 terminal ECM terminal 13 511 6
25 627 5
Continuity should not exist.
Revision: April 20092010 QX56

EC-394
< COMPONENT DIAGNOSIS >[VK56DE]
ELECTRICAL LOAD SIGNAL
ELECTRICAL LOAD SIGNAL
DescriptionINFOID:0000000005149471
The electrical load signal (Headlamp switch signal, r
ear window defogger switch signal, etc.) is transferred
through the CAN communication line from BCM to ECM via IPDM E/R.
Diagnosis ProcedureINFOID:0000000005149472
1.CHECK LOAD SIGNAL CIRCUIT OVERALL FUNCTION-I
1. Turn ignition switch ON.
2. Connect CONSULT-III and select “DATA MONITOR” mode.
3. Select “LOAD SIGNAL” and check indication under the following conditions.
OK or NG
OK >> GO TO 2.
NG >> GO TO 4.
2.CHECK LOAD SIGNAL CIRCUIT OVERALL FUNCTION-II
Check “LOAD SIGNAL” indication under the following conditions.
OK or NG
OK >> GO TO 3.
NG >> GO TO 5.
3.CHECK HEATER FAN SIGNAL CIRCUIT OVERALL FUNCTION
Select “HEATER FAN SW” and check indication under the following conditions.
OK or NG
OK >> INSPECTION END
NG >> GO TO 6.
4.CHECK REAR WINDOW DEFOGGER SYSTEM
Refer to DEF-4
.
>> INSPECTION END
5.CHECK HEADLAMP SYSTEM
Refer to EXL-7
, or EXL-9.
>> INSPECTION END
6.CHECK HEATER FAN CONTROL SYSTEM
Refer to HAC-47
.
Condition Indication
Rear window defogger switch: ON ON
Rear window defogger switch: OFF OFF
ConditionIndication
Lighting switch: ON at 2nd position ON
Lighting switch: OFF OFF
ConditionIndication
Heater fan control switch: ON ON
Heater fan control switch: OFF OFF
Revision: April 20092010 QX56

ECM
EC-423
< ECU DIAGNOSIS > [VK56DE]
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LOAD SIGNAL • Ignition switch: ON
Rear window defogger switch is ON
and/or lighting switch is in 2nd.
ON
Rear window defogger switch is OFF
and lighting switch is OFF. OFF
IGNITION SW • Ignition switch: ON → OFF → ON ON → OFF → ON
HEATER FAN SW • Engine: After warming up, idle the
engine Heater fan control switch: ON ON
Heater fan control switch: OFF OFF
BRAKE SW • Ignition switch: ON Brake pedal: Fully released
OFF
Brake pedal: Slightly depressed ON
INJ PULSE-B1
INJ PULSE-B2 • Engine: After warming up
• Selector lever: P or N
• Air conditioner switch: OFF
• No load Idle
2.0 - 2.8 msec
2,000 rpm 1.9 - 2.9 msec
IGN TIMING • Engine: After warming up
• Selector lever: P or N
• Air conditioner switch: OFF
• No load Idle
10° - 20 ° BTDC
2,000 rpm 25° - 45 ° BTDC
CAL/LD VALUE • Engine: After warming up
• Selector lever: P or N
• Air conditioner switch: OFF
• No load Idle
14% - 33%
2,500 rpm 12% - 25%
MASS AIRFLOW • Engine: After warming up
• Selector lever: P or N
• Air conditioner switch: OFF
• No load Idle
3.0 - 9.0 g·m/s
2,500 rpm 9.0 - 28.0 g·m/s
PURG VOL C/V • Engine: After warming up
• Selector lever: P or N
• Air conditioner switch: OFF
• No load Idle
(Accelerator pedal: Not depressed
even slightly, after engine starting.)
0%
2,000 rpm —
INT/V TIM (B1)
INT/V TIM (B2) • Engine: After warming up
• Selector lever: P or N
• Air conditioner switch: OFF
• No load Idle
−5° - 5 °CA
2,000 rpm Approx. 0° - 20°CA
INT/V SOL (B1)
INT/V SOL (B2) • Engine: After warming up
• Selector lever: P or N
• Air conditioner switch: OFF
• No load Idle
0% - 2%
2,000 rpm Approx. 25% - 50%
AIR COND RLY • Engine: After warming up, idle the
engine Air conditioner switch: OFF
OFF
Air conditioner switch: ON
(Compressor: Operates) ON
FUEL PUMP RLY • For 1 second after turning ignition switch ON
•
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ngine running or cranking ON
• Except above conditions OFF
VENT CONT/V • Ignition switch: ON OFF
THRTL RELAY • Ignition switch: ON ON
COOLING FAN • Engine: After warming up, idle the
engine
• Air conditioner switch: OFF Engine coolant temperature: 99
°C
(210 °F) or less OFF
Engine coolant temperature: 100 °C
(212 °F) or more HI
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 load ON
• Engine speed: Above 3,600 rpm OFF
MONITOR ITEM
CONDITION SPECIFICATION
Revision: April 20092010 QX56

ECM
EC-425
< ECU DIAGNOSIS > [VK56DE]
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ECM Harness Connector Terminal LayoutINFOID:0000000005149493
ECM Terminal and Reference ValueINFOID:0000000005149494
PREPARATION
ECM is located in the engine room passenger side behind battery.
ECM INSPECTION TABLE
Specification data are reference values and are measured between each terminal and ground.
Pulse signal is measured by CONSULT-IIl.
CAUTION:
Do not use ECM ground terminals wh
en measuring input/output voltage. Doing so may result in dam-
age to the ECMs transistor. Use a ground ot her than ECM terminals, such as the ground.
PBIB3368E
BBIA0386E
TER-
MI-
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NO. WIRE
COLOR ITEM
CONDITION DATA (DC Voltage)
1 B ECM ground [Engine is running]
• Idle speedBody ground
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
3L Throttle contro
l motor relay
power supply [Ignition switch: ON] BATTERY VOLTAGE
(11 - 14V)
4 L/W Throttle cont rol motor (Close)[Ignition switch: ON]
• Engine: Stopped
• Selector lever: D
• Accelerator pedal: Fully released 0 - 14V
PBIA8148J
PBIB1104E
Revision: April 20092010 QX56

EC-428
< ECU DIAGNOSIS >[VK56DE]
ECM
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44O/L
BR
GR/W
O Fuel injector No. 5
Fuel injector No. 3
Fuel injector No. 1
Fuel injector No. 7 [Engine is running]
•
Warm-up condition
• Idle speed
NOTE:
The pulse cycle changes depending on rpm at
idle BATTERY VOLTAGE
(11 - 14V)
[Engine is running]
• Warm-up condition
• Engine speed: 2,000 rpm BATTERY VOLTAGE
(11 - 14V)
24
43 GR/G
GR/G
A/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
25 O/G Heated oxygen sensor 2 heat-
er (bank 2) [Engine is running]
• 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 load 0 - 1.0V
[Ignition switch: ON]
• Engine: Stopped
[Engine is running]
• Engine speed: Above 3,600 rpm BATTERY VOLTAGE
(11 - 14V)
32 L EVAP control system pres-
sure sensor
[Ignition switch: ON]
Approximately 1.8 - 4.8V
34 R/B Intake air temperature sensor [Engine is running]Approximately 0 - 4.8V
Output voltage varies with intake
air temperature.
35 O A/F sensor 1 (bank 1) [Engine is running]
•
Warm-up condition
• Engine speed: 2,000 rpm Approximately 1.8V
Output voltage varies with air fuel
ratio.
36 W Knock sensor (bank 2) [Engine is running]
• Idle speedApproximately 2.5V
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COLOR ITEM
CONDITION DATA (DC Voltage)SEC984C
SEC985C
PBIA8148J
Revision: April 20092010 QX56

EC-458
< ECU DIAGNOSIS >[VK56DE]
ECM
DTC Inspection Priority Chart
INFOID:0000000005149497
If some DTCs are displayed at the same time, perform inspections one by one based on the following priority
chart.
Priority Detected items (DTC)
1 • U0101 CAN communication line • U1001 CAN communication line
• P0101 P0102 P0103 Mass air flow sensor
• P0112 P0113 P0127 Intake air temperature sensor
• P0116 P0117 P0118 P0125 Engine coolant temperature sensor
• P0122 P0123 P0222 P0223 P1225 P1226 P2135 Throttle position sensor
• P0128 Thermostat function
• P0181 P0182 P0183 Fuel tank temperature sensor
• P0327 P0328 P0332 P0333 Knock sensor
• P0335 Crankshaft position sensor (POS)
• P0340 Camshaft position sensor (PHASE)
• P0460 P0461 P0462 P0463 Fuel level sensor
• P0500 Vehicle speed sensor
• P0605 P0607 ECM
• P0643 Sensor power supply
• P0700 TCM
• P0705 Park/neutral position (PNP) switch
• P0850 Park/neutral position (PNP) switch
• P1550 P1551 P1552 P1553 P1554 Battery current sensor
• P1610 - P1615 NATS
• P2122 P2123 P2127 P2128 P2138 Accelerator pedal position sensor
2 • P0031 P0032 P0051 P0052 Air fuel ratio (A/F) sensor 1 heater • P0037 P0038 P0057 P0058 Heated oxygen sensor 2 heater
• P0075 P0081 Intake valve timing control solenoid valve
• P0130 P0131 P0132 P0133 P0150 P0151 P0152 P0153 P2A00 P2A03 Air fuel ratio (A/F) sensor 1
• P0137 P0138 P0139 P0157 P0158 P0159 Heated oxygen sensor 2
• P0441 EVAP control system purge flow monitoring
• P0443 P0444 P0445 EVAP canister purge volume control solenoid valve
• P0447 P0448 EVAP canister vent control valve
• P0451 P0452 P0453 EVAP control system pressure sensor
• P0550 Power steering pressure sensor
• P0603 ECM power supply
• P0710 P0717 P0720 P0731 P0732 P0733 P0734 P0735 P0740 P0744 P0745 P1730 P1752 P1757 P1762 P1767 P1772 P1774 A/T related sensors, solenoid valves and switches
• P1217 Engine over temperature (OVERHEAT)
• P1140 P1145 Intake valve timing control position sensor
• P1805 Brake switch
• P2100 P2103 P2118 Electric throttle control actuator
• P2101 Electric throttle control function
3 • P0011 P0021 Intake valve timing control • P0171 P0172 P0174 P0175 Fuel injection system function
• P0300 - P0308 Misfire
• P0420 P0430 Three way catalyst function
• P0442 EVAP control system (SMALL LEAK)
• P0455 EVAP control system (GROSS LEAK)
• P0456 EVAP control sys tem (VERY SMALL LEAK)
• P0506 P0507 Idle speed control system
• P1148 P1168 Closed loop control
• P1211 TCS control unit
• P1212 TCS communication line
• P1421 Cold start control
• P1564 ICC/ASCD steering switch
• P1568 ICC command value
• P1572 ICC/ASCD brake switch
• P1574 ICC/ASCD vehicle speed sensor
• P2119 Electric throttle control actuator
Revision: April 20092010 QX56