Infiniti QX56 (JA60). Manual - part 357

EC-80

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TROUBLE DIAGNOSIS - SPECIFICATION VALUE

2. Disconnect mass air flow sensor harness connector. Check pin terminal and connector for damage and

then reconnect it again.

>> GO TO 22.

22.

CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”

1. Start engine.

2. Select “A/F ALPHA-B1”, “A/F ALPHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the

each indication is within the SP value.

OK or NG

OK

>> 1. Detect malfunctioning part of mass air flow sensor circuit and repair it. Refer to 

EC-110

.

2. GO TO 29.

NG

>> GO TO 23.

23.

CHECK “MAS A/F SE-B1”

Select “MAS A/F SE-B1” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the

SP value.
OK or NG

OK

>> GO TO 24.

NG (More than the SP value)>>Replace mass air flow sensor, and then GO TO 29.

24.

REPLACE ECM

1. Replace ECM.

2. Perform initialization of IVIS(NATS) system and registration of all IVIS(NATS) ignition key IDs. Refer to

SEC-9, "ECM RE-COMMUNICATING FUNCTION : Special Repair Requirement"

.

3. Perform 

EC-17, "VIN Registration"

.

4. Perform 

EC-18, "Accelerator Pedal Released Position Learning"

.

5. Perform 

EC-18, "Throttle Valve Closed Position Learning"

.

6. Perform 

EC-18, "Idle Air Volume Learning"

.

>> GO TO 29.

25.

CHECK INTAKE SYSTEM

Check for the cause of uneven air flow through mass air flow sensor. Refer to the following.

• Crushed air ducts

• Malfunctioning seal of air cleaner element

• Uneven dirt of air cleaner element

• Improper specification of intake air system
OK or NG

OK

>> GO TO 27.

NG

>> Repair or replace malfunctioning part, and then GO TO 26.

26.

CHECK “B/FUEL SCHDL”

Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the

SP value.
OK or NG

OK

>> INSPECTION END

NG (Less than the SP value)>>GO TO 27.

27.

CHECK “MAS A/F SE-B1”

Select “MAS A/F SE-B1” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the

SP value.
OK or NG

OK

>> GO TO 28.

NG (Less than the SP value)>>Replace mass air flow sensor, and then GO TO 30.

28.

CHECK INTAKE SYSTEM

Check for the cause of air leak after the mass air flow sensor. Refer to the following.

TROUBLE DIAGNOSIS - SPECIFICATION VALUE

EC-81

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• Disconnection, looseness, and cracks in air duct

• Looseness of oil filler cap

• Disconnection of oil level gauge

• Open stuck, breakage, hose disconnection, or cracks of PCV valve

• Disconnection or cracks of EVAP purge hose, open stuck of EVAP canister purge volume control solenoid

valve

• Malfunctioning seal of rocker cover gasket

• Disconnection, looseness, or cracks of hoses, such as vacuum hose, connecting to intake air system parts

• Malfunctioning seal of intake air system, etc.

>> GO TO 30.

29.

CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”, AND “B/FUEL SCHDL”

Select “A/F ALPHA-B1”, “A/F ALPHA-B2”, and “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and

make sure that the each indication is within the SP value. 
OK or NG

OK

>> INSPECTION END

NG

>> Detect malfunctioning part according to 

EC-477, "Symptom Matrix Chart"

.

30.

CHECK “B/FUEL SCHDL”

Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and then make sure that the indication is

within the SP value.
OK or NG

OK

>> INSPECTION END

NG

>> Detect malfunctioning part according to 

EC-477, "Symptom Matrix Chart"

.

EC-82

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POWER SUPPLY AND GROUND CIRCUIT

POWER SUPPLY AND GROUND CIRCUIT

Diagnosis Procedure

INFOID:0000000005149085

1.

INSPECTION START

Start engine.

Is engine running?
Yes or No

Yes

>> GO TO 8.

No

>> GO TO 2.

2.

CHECK ECM POWER SUPPLY CIRCUIT-I

1. Turn ignition switch OFF and then ON.

2. Check voltage between ECM terminal 109 and ground with

CONSULT-III or tester.

OK or NG

OK

>> GO TO 4.

NG

>> GO TO 3.

3.

DETECT MALFUNCTIONING PART

Check the following.

• 10A fuse (No. 59)

• Harness for open or short between ECM and fuse

>> Repair harness or connectors.

4.

CHECK GROUND CONNECTIONS

1. Turn ignition switch OFF.

2. Loosen and retighten three ground screws on the body.

Refer to 

EC-85, "Ground Inspection"

.

OK or NG

OK

>> GO TO 5.

NG

>> Repair or replace ground connections.

5.

CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-I

1. Disconnect ECM harness connector.

2. Check harness continuity between ECM terminals 1, 115, 116 and ground.

Refer to Wiring Diagram.

3. Also check harness for short to power.

Voltage: Battery voltage

MBIB0015E

BBIA0354E

Continuity should exist.

POWER SUPPLY AND GROUND CIRCUIT

EC-83

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OK or NG

OK

>> GO TO 7.

NG

>> GO TO 6.

6.

DETECT MALFUNCTIONING PART

Check the following.

• Harness connectors F32, E2

• Harness for open or short between ECM and ground

>> Repair open circuit or short to power in harness or connectors.

7.

CHECK ECM POWER SUPPLY CIRCUIT-II

1. Reconnect ECM harness connector.

2. Turn ignition switch ON.

3. Check voltage between IPDM E/R terminal 4 and ground with

CONSULT-III or tester.

OK or NG

OK

>> Go to 

EC-407, "Diagnosis Procedure"

.

NG

>> GO TO 8.

8.

CHECK ECM POWER SUPPLY CIRCUIT-III

1. Turn ignition switch OFF and wait at least 10 seconds.

2. Turn ignition switch ON and then OFF.

3. Check voltage between ECM terminals 119, 120 and ground

with CONSULT-III or tester.

OK or NG

OK

>> GO TO 13.

NG (Battery voltage does not exist.)>>GO TO 9.

NG (Battery voltage exists for more than a few seconds.)>>GO  TO

11.

9.

CHECK ECM POWER SUPPLY CIRCUIT-IV

1. Turn ignition switch OFF and wait at least 10 seconds.

2. Check voltage between ECM terminal 111 and ground with

CONSULT-III or tester.

OK or NG

OK

>> GO TO 10.

NG

>> GO TO 11.

10.

CHECK ECM POWER SUPPLY CIRCUIT-V

1. Disconnect ECM harness connector.

2. Disconnect IPDM E/R harness connector E119.

3. Check harness continuity between ECM terminals 119, 120 and IPDM E/R terminal 3.

Voltage: Battery voltage

PBIB2063E

Voltage:

After turning ignition switch OFF, battery 
voltage will exist for a few seconds, then drop 
approximately 0 V.

PBIB1630E

Voltage: Battery voltage

PBIB1191E