Diagnosis Procedure

WARNING: This page is about a different car, the 2013 Infiniti FX50. However, it is still accessible from the selected car via links, so may be relevant.

CHECK FOR INTAKE AIR LEAKAGE AND PCV HOSE
1. Start engine and run it at idle speed.
2. Listen for the sound of the intake air leakage.
3. Check PCV hose connection.
  Is intake air leakage detected?
  
  YES: Discover air leakage location and repair.
  
  NO: GO TO 2.
CHECK FOR EXHAUST SYSTEM CLOGGING
Stop engine and visually check exhaust tube, three way catalyst and muffler for dents.

Is the inspection result normal?

YES-1: With CONSULT: GO TO 3.

YES-2: Without CONSULT: GO TO 4.

NO: Repair or replace malfunctioning part.
PERFORM POWER BALANCE TEST
With CONSULT
1. Start engine.
2. Perform "POWER BALANCE" in "ACTIVE TEST" mode with CONSULT.
3. Check that each circuit produces a momentary engine speed drop.
  Is the inspection result normal?
  
  YES: GO TO 9.
  
  NO: GO TO 4.
CHECK FUNCTION OF FUEL INJECTOR-I
1. Start engine and let it idle.
2. Listen to each fuel injector operation.
  Clicking sound should be heard.
  
  Fig 1: Listening For Fuel Injector Operating Sound
  Courtesy of NISSAN NORTH AMERICA, INC.
  
  Is the inspection result normal?
  
  YES: GO TO 5.
  
  NO: Perform trouble diagnosis for FUEL INJECTOR, refer to "DIAGNOSIS PROCEDURE ".
CHECK FUNCTION OF IGNITION COIL-I
CAUTION: Perform the following procedure in a place with no combustible objects and good ventilation.
1. Turn ignition switch OFF.
2. Remove fuel pump fuse (1) in IPDM E/R (2) to release fuel pressure.
  NOTE: Do not use CONSULT to release fuel pressure, or fuel pressure applies again during the following procedure.
  
  Fig 2: Locating Fuel Pump Fuse And IPDM E/R
  Courtesy of NISSAN NORTH AMERICA, INC.
3. Start engine.
4. After engine stalls, crank it 2 or 3 times to release all fuel pressure.
5. Turn ignition switch OFF.
6. Remove all ignition coil harness connectors to avoid the electrical discharge from the ignition coils.
7. Remove ignition coil and spark plug of the cylinder to be checked.
8. Crank engine for 5 seconds or more to remove combustion gas in the cylinder.
9. Connect spark plug and harness connector to ignition coil.
10. Fix ignition coil using a rope etc. with gap of 13 - 17 mm (0.52 - 0.66 in) between the edge of the spark plug and grounded metal portion as shown in the figure below.
11. Crank engine for approximately 3 seconds, and check whether spark is generated between the spark plug and the grounded metal portion.
  Spark should be generated.
  CAUTION:
  - Never place the spark plug and the ignition coil within 50 cm (19.7 in) each other. Be careful not to get an electrical shock while checking, because the electrical discharge voltage becomes 20 kV or more.
  - It might damage the ignition coil if the gap of more than 17 mm (0.66 in) is made.
  Fig 3: Identifying Gap Between Edge Of Spark Plug And Grounded Metal Portion
  Courtesy of NISSAN NORTH AMERICA, INC.
  
  NOTE: When the gap is less than 13 mm (0.52 in), a spark might be generated even if the coil is malfunctioning.
  
  Is the inspection result normal?
  
  YES: GO TO 9.
  
  NO: GO TO 6.
CHECK FUNCTION OF IGNITION COIL-II
1. Turn ignition switch OFF.
2. Disconnect spark plug and connect a non-malfunctioning spark plug.
3. Crank engine for approximately 3 seconds, and recheck whether spark is generated between the spark plug and the grounded metal portion.
  Spark should be generated.
  
  Is the inspection result normal?
  
  YES: GO TO 7.
  
  NO: Check ignition coil, power transistor and their circuits. Refer to "DIAGNOSIS PROCEDURE ".
CHECK SPARK PLUG
Check the initial spark plug for fouling, etc.

Is the inspection result normal?

YES: Replace spark plug(s) with standard type one(s). For spark plug type, refer to "SPARK PLUG ".

NO: Repair or clean spark plug. Then GO TO 8.

Fig 4: Identifying Fouling Area On Spark Plug
Courtesy of NISSAN NORTH AMERICA, INC.
CHECK FUNCTION OF IGNITION COIL-III
1. Reconnect the initial spark plugs.
2. Crank engine for approximately 3 seconds, and recheck whether spark is generated between the spark plug and the grounded portion.
  Spark should be generated.
  
  Is the inspection result normal?
  
  YES: INSPECTION END
  
  NO: Replace spark plug(s) with standard type one(s). For spark plug type, refer to "SPARK PLUG ".
CHECK COMPRESSION PRESSURE
Check compression pressure. Refer to "INSPECTION ".

Is the inspection result normal?

YES: GO TO 10.

NO: Check pistons, piston rings, valves, valve seats and cylinder head gaskets.
CHECK FUEL PRESSURE
1. Install all removed parts.
2. Check fuel pressure. Refer to "INSPECTION ".
  Is the inspection result normal?
  
  YES: GO TO 12.
  
  NO: GO TO 11.
DETECT MALFUNCTIONING PART
Check fuel hoses and fuel tubes for clogging.

Is the inspection result normal?

YES: Replace "fuel filter and fuel pump assembly". Refer to "REMOVAL AND INSTALLATION ".

NO: Repair or replace malfunctioning part.
CHECK IDLE SPEED AND IGNITION TIMING
Check idle speed and ignition timing.

For procedure, refer to "BASIC INSPECTION: SPECIAL REPAIR REQUIREMENT ".

For specification, refer to "IDLE SPEED " and "IGNITION TIMING ".

Is the inspection result normal?

YES: GO TO 13.

NO: Follow the "BASIC INSPECTION: SPECIAL REPAIR REQUIREMENT ".

CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT

Turn ignition switch OFF.
Disconnect corresponding A/F sensor 1 harness connector.
Disconnect ECM harness connector.

Check the continuity between A/F sensor 1 harness connector and ECM harness connector.

A/F sensor 1			ECM		Continuity
Bank	Connector	Terminal	Connector	Terminal	Continuity
1	F131	1	F111	81	Existed
1	F131	2		82
2	F132	1		85
2	F132	2		86

Check the continuity between A/F sensor 1 harness connector and ground, or ECM harness connector and ground.

A/F sensor 1			ECM		Ground	Continuity
Bank	Connector	Terminal	Connector	Terminal	Ground	Continuity
1	F131	1	F111	81	Ground	Not existed
1	F131	2		82
2	F132	1		85
2	F132	2		86

Also check harness for short to power.
Is the inspection result normal?

YES: GO TO 14.

NO: Repair open circuit, short to ground or short to power in harness or connectors.

CHECK A/F SENSOR 1 HEATER
Refer to "COMPONENT INSPECTION ".

Is the inspection result normal?

YES: GO TO 15.

NO: Replace malfunctioning A/F sensor 1. Refer to "EXPLODED VIEW ".
CHECK MASS AIR FLOW SENSOR
With CONSULT

Check mass air flow sensor signal in "DATA MONITOR" mode with CONSULT.

For specification, refer to "MASS AIR FLOW SENSOR ".

With GST

Check mass air flow sensor signal in Service $01 with GST.

For specification, refer to "MASS AIR FLOW SENSOR ".

Is the measurement value within the specification?

YES: GO TO 16.

NO: Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or ground. Refer to "DIAGNOSIS PROCEDURE ".
CHECK SYMPTOM MATRIX CHART
Check items on the rough idle symptom in "SYMPTOM TABLE ".

Is the inspection result normal?

YES: GO TO 17.

NO: Repair or replace malfunctioning part.
ERASE THE 1ST TRIP DTC
Some tests may cause a 1st trip DTC to be set.

Erase the 1st trip DTC from the ECM memory after performing the tests. Refer to "ON BOARD DIAGNOSIS FUNCTION " (Without CONSULT) or "CONSULT FUNCTION " (With CONSULT).

: GO TO 18.
CHECK INTERMITTENT INCIDENT
Refer to "INTERMITTENT INCIDENT ".

: INSPECTION END