2008 INFINITI QX56 wiring diagram

P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
EC-179
< COMPONENT DIAGNOSIS > [VK56DE]
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The similar conditions to (1st trip) Freeze Frame Da
ta means the vehicle operation that the following con-
ditions should be satisfied at the same time.
10. If it is difficult to start engine at step 8, the fuel injection system has a malfunction.
11. Crank engine while depressing accelerator pedal. If engine starts, go to EC-179, "
Diagnosis Procedure".
If engine does not start, check exhaust and intake air leak visually.
Diagnosis ProcedureINFOID:0000000001351516
1.CHECK EXHAUST GAS LEAK
1. Start engine and run it at idle.
2. Listen for an exhaust gas leak before three way catalyst (manifold).
OK or NG
OK >> GO TO 2.
NG >> Repair or replace.
2.CHECK FOR INTAKE AIR LEAK
1. Listen for an intake air leak after the mass air flow sensor.
2. Check PCV hose connection.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace.
3.CHECK A/F SENSOR 1 IN PUT SIGNAL CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect corresponding A/F sensor 1 harness connector.
3. Disconnect ECM harness connector.
4. Check harness continuity between the following terminals. Refer to Wiring Diagram.
Engine speed Engine speed in the freeze frame data ± 400 rpm
Vehicle speed Vehicle speed in the freeze frame data ± 10 km/h (6 MPH)
Engine coolant temperature (T)
condition When the freeze frame data shows lower than 70
°C (158 °F),
T should be lower than 70 °C (158 °F).
When the freeze frame data shows higher than or equal to 70 ° C (158 °F),
T should be higher than or equal to 70 °C (158 °F).
PBIB1216E
BBIA0376E
Revision: March 2010 2008 QX56

EC-180
< COMPONENT DIAGNOSIS >[VK56DE]
P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
5. Check harness continuity between the following terminals and ground.
Refer to Wiring Diagram.
6. Also check harness for 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 FUEL PRESSURE
1. Release fuel pressure to zero. Refer to EC-494, "
Fuel Pressure Check".
2. Install fuel pressure gauge and check fuel pressure. Refer to EC-494, "
Fuel Pressure Check".
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5.DETECT MALFUNCTIONING PART
Check the following.
• Fuel pump and circuit (Refer to EC-402, "
Diagnosis Procedure".)
• Fuel pressure regulator (Refer to EC-494, "
Fuel Pressure Check".)
• Fuel lines
• Fuel filter for clogging
>> Repair or replace.
6.CHECK MASS AIR FLOW SENSOR
With CONSULT-III
1. Install all removed parts.
2. Check “MASS AIR FLOW” in “DATA MONITOR” mode with CONSULT-III.
With GST
1. Install all removed parts.
2. Check mass air flow sensor signal in Service $01 with GST.
A/F sensor 1 terminal ECM terminal
Bank 1 13
5
25 6
Bank 2 11
6
27 5
Continuity should exist.
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.
At idling: Approximately 350 kPa (3.57 kg/cm2, 51 psi)
3.0 - 9.0 g·m/sec: at idling
9.0 - 28.0 g·m/sec: at 2,500 rpm
Revision: March 2010 2008 QX56

P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
EC-185
< COMPONENT DIAGNOSIS > [VK56DE]
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EC
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Hold the accelerator pedal as steady as possible.
The similar conditions to (1st trip) Freeze Frame Da
ta means the vehicle operation that the following con-
ditions should be satisfied at the same time.
9. If it is difficult to start engine at step 7, the fuel injection system has a malfunction.
10. Crank engine while depressing accelerator pedal. If engine starts, go to EC-185, "
Diagnosis Procedure". If engine does not start, remove spark plugs and
check for fouling, etc.
Diagnosis ProcedureINFOID:0000000001351520
1.CHECK EXHAUST GAS LEAK
1. Start engine and run it at idle.
2. Listen for an exhaust gas leak before three way catalyst (manifold).
OK or NG
OK >> GO TO 2.
NG >> Repair or replace.
2.CHECK FOR INTAKE AIR LEAK
Listen for an intake air leak after the mass air flow sensor.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace.
3.CHECK A/F SENSOR 1 IN PUT SIGNAL CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect corresponding A/F sensor 1 harness connector.
3. Disconnect ECM harness connector.
4. Check harness continuity between the following terminals. Refer to Wiring Diagram.
Engine speed Engine speed in the freeze frame data ± 400 rpm
Vehicle speed Vehicle speed in the freeze frame data ± 10 km/h (6 MPH)
Engine coolant temperature (T)
condition When the freeze frame data shows lower than 70
°C (158 °F),
T should be lower than 70 °C (158 °F).
When the freeze frame data shows higher than or equal to 70 ° C (158 °F),
T should be higher than or equal to 70 °C (158 °F).
PBIB1216E
BBIA0376E
Revision: March 2010 2008 QX56

EC-186
< COMPONENT DIAGNOSIS >[VK56DE]
P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
5. Check harness continuity between the following terminals and ground.
Refer to Wiring Diagram.
6. Also check harness for 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 FUEL PRESSURE
1. Release fuel pressure to zero. Refer to EC-494, "
Fuel Pressure Check".
2. Install fuel pressure gauge and check fuel pressure. Refer to EC-494, "
Fuel Pressure Check".
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5.DETECT MALFUNCTIONING PART
Check the following.
• Fuel pump and circuit (Refer to EC-402, "
Diagnosis Procedure".)
• Fuel pressure regulator (Refer to EC-494, "
Fuel Pressure Check".)
>> Repair or replace.
6.CHECK MASS AIR FLOW SENSOR
With CONSULT-III
1. Install all removed parts.
2. Check “MASS AIR FLOW” in “DATA MONITOR” mode with CONSULT-III.
With GST
1. Install all removed parts.
2. Check mass air flow sensor signal in Service $01 with GST.
OK or NG
A/F sensor 1 terminal ECM terminal
Bank 1 13
5
25 6
Bank 2 11
6
27 5
Continuity should exist.
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.
At idling: Approximately 350 kPa (3.57 kg/cm2, 51 psi)
3.0 - 9.0 g·m/sec: at idling
9.0 - 28.0 g·m/sec: at 2,500 rpm
3.0 - 9.0 g·m/sec: at idling
9.0 - 28.0 g·m/sec: at 2,500 rpm
Revision: March 2010 2008 QX56

P0181 FTT SENSOREC-189
< COMPONENT DIAGNOSIS > [VK56DE]
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WITH GST
Follow the procedure “WITH CONSULT-III” above.
Diagnosis ProcedureINFOID:0000000001351525
1.CHECK FUEL TANK TEMPERATURE
SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect “fuel level sensor unit and fuel pump” harness con- nector.
3. Turn ignition switch ON.
4. Check voltage between “fuel level sensor unit and fuel pump” terminal 4 and ground with CONSULT-III or tester.
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
2.DETECT MALFUNCTIONING PART
Check the following.
• Harness connectors C1, E41
• Harness for open or short between ECM and “fuel level sensor unit and fuel pump”
>> Repair harness or connector.
3.CHECK FUEL TANK TEMPERATURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Check harness continuity between “fuel level sensor unit and fuel pump” terminal 3 and ground. Refer to Wiring Diagram.
3. Also check harness for short to power.
OK or NG
OK >> GO TO 5.
NG >> GO TO 4.
4.DETECT MALFUNCTIONING PART
Check the following.
• Harness connectors C1, E41
• Harness for open or short between “fuel level sensor unit and fuel pump” and ground
>> Repair open circuit or short to power in harness or connector.
5.CHECK FUEL TANK TEMPERATURE SENSOR
BBIA0583E
Voltage: Approximately 5V
PBIB0932E
Continuity should exist.
Revision: March 2010 2008 QX56

EC-192
< COMPONENT DIAGNOSIS >[VK56DE]
P0182, P0183
FTT SENSOR
2. Disconnect “fuel level sensor unit and fuel pump” harness con-
nector.
3. Turn ignition switch ON.
4. Check voltage between “fuel level sensor unit and fuel pump”
terminal 4 and ground with CONSULT-III or tester.
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
2.DETECT MALFUNCTIONING PART
Check the following.
• Harness connectors C1, E41
• Harness for open or short between ECM and “fuel level sensor unit and fuel pump”
>> Repair harness or connector.
3.CHECK FUEL TANK TEMPERATURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Check harness continuity between “fuel level sensor unit and fuel pump” terminal 3 and ground. Refer to
Wiring Diagram.
3. Also check harness for short to power.
OK or NG
OK >> GO TO 5.
NG >> GO TO 4.
4.DETECT MALFUNCTIONING PART
Check the following.
• Harness connectors C1, E41
• Harness for open or short between “fuel level sensor unit and fuel pump” and ground
>> Repair open circuit or short to power in harness or connector.
5.CHECK FUEL TANK TEMPERATURE SENSOR
Refer to EC-193, "
Component Inspection".
OK or NG
OK >> GO TO 6.
NG >> Replace “fuel level sensor unit and fuel pump”.
6.CHECK INTERMITTENT INCIDENT
Refer to GI-35, "
How to Check Terminal" and GI-38, "Intermittent Incident".
BBIA0583E
Voltage: Approximately 5V
PBIB0932E
Continuity should exist.
Revision: March 2010 2008 QX56

P0222, P0223 APP SENSOREC-195
< COMPONENT DIAGNOSIS > [VK56DE]
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Refer to
EC-86, "Ground Inspection".
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2.CHECK THROTTLE POSITION SENSOR 1 POWER SUPPLY CIRCUIT-I
1. Disconnect electric throttle c ontrol actuator (1) harness connec-
tor.
- Illustration shows the view with intake air duct removed.
2. Turn ignition switch ON.
3. Check voltage between electric throttle control actuator terminal 2 and ground with CONSULT-III or tester.
OK or NG
OK >> GO TO 7.
NG >> GO TO 3.
3.CHECK THROTTLE POSITION SENSOR 1 POWER SUPPLY CIRCUIT-II
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between electric thrott le control actuator terminal 2 and ECM terminal 47.
Refer to Wiring Diagram.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit.
4.CHECK THROTTLE POSITION SENSOR 1 POWER SUPPLY CIRCUIT-III
Check harness for short to power and short to ground, between the following terminals.
BBIA0354E
BBIA0371E
Voltage: Approximately 5V
PBIB2065E
Continuity should exist.
ECM terminalSensor terminal Reference Wiring Diagram
47 Electric throttle control actuator terminal 2
EC-439, "
Wiring Diagram - ENGINE
CONTROL SYSTEM -"91APP sensor terminal 6
Revision: March 2010 2008 QX56

EC-196
< COMPONENT DIAGNOSIS >[VK56DE]
P0222, P0223 APP SENSOR
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-384, "
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-18, "
Accelerator Pedal Released Position Learning".
3. Perform EC-18, "
Throttle Valve Closed Position Learning".
4. Perform EC-18, "
Idle Air Volume Learning".
>> INSPECTION END
7.CHECK THROTTLE POSITION SENSOR 1 GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between electric thrott le 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 1 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between ECM terminal 50 and electric throttle control actuator terminal 1. 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-197, "
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-18, "
Throttle Valve Closed Position Learning".
3. Perform EC-18, "
Idle Air Volume Learning".
>> INSPECTION END
11 .CHECK INTERMITTENT INCIDENT
Refer to GI-35, "
How to Check Terminal" and GI-38, "Intermittent Incident".
Continuity should exist.
Continuity should exist.
Revision: March 2010
2008 QX56