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Home >> Infiniti >> 2024 >> QX55 Essential >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System (2 Of 2) >> Symptom Diagnosis >> Engine Control System >> Symptom Table
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Symptom Table

SYSTEM - BASIC ENGINE CONTROL SYSTEM 

  SYMPTOM Reference
HARD/NO START/RESTART (EXCP. HA) ENGINE STALL HESITATION/SURGING/FLAT SPOT SPARK KNOCK/DETONATION LACK OF POWER/POOR ACCELERATION HIGH IDLE/LOW IDLE ROUGH IDLE/HUNTING IDLING VIBRATION SLOW/NO RETURN TO IDLE OVERHEATS/WATER TEMPERATURE HIGH EXCESSIVE FUEL CONSUMPTION EXCESSIVE OIL CONSUMPTION BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA  
Fuel Fuel pump circuit 1 1 2 3 2   2 2     3   2 Component Function Check
Fuel pressure regulator system 3 3 4 4 4 4 4 4 4   4     Work Procedure
Direct fuel injector circuit 1 1 2 3 2   2 2     2     Diagnosis Procedure
Port fuel injector circuit 1 1 2 3 2   2 2     2     Diagnosis Procedure
Evaporative emission system 3 3 4 4 4 4 4 4 4   4     Inspection 
Fuel rail pressure sensor circuit 1 1 2 2 2   2 2     2     DTC Description
High pressure fuel pump circuit     4   3                 Component Function Check
Air Positive crankcase ventilation system 3 3 4 4 4 4 4 4 4   4 1   Inspection 
Incorrect idle speed adjustment       1 1 1 1   1     Work Procedure
Electric throttle control actuator 1 1 2 3 3 2 2 2 2   2   2 DTC Description , DTC Description
Intake manifold runner control valve circuit       4 4                 DTC Description
Ignition Incorrect ignition timing adjustment 3 3 1 1 1   1 1     1     Work Procedure
Ignition circuit 1 1 2 2 2   2 2     2     Component Function Check
Main power supply and ground circuit 2 2 3 3 3   3 3   2 3     Diagnosis Procedure
Main power supply and ground circuit 1 1 2 2 2   2 2     2     Diagnosis Procedure
Mass air flow sensor circuit 2            
Engine coolant temperature sensor circuit 3 3 3       DTC Description
Air fuel ratio (A/F) sensor 1 circuit             DTC Description , DTC Description , DTC Description
Throttle position sensor circuit     2 2       DTC Description , DTC Description , DTC Description , DTC Description , DTC Description
Accelerator pedal position sensor circuit     3 2 1             DTC Description , DTC Description , DTC Description
Heated oxygen sensor 2 circuit     6   6   6 6     5      
Knock sensor circuit     2               3     DTC Description
Engine oil temperature sensor circuit     4   2           3     DTC Description
Engine oil pressure sensor circuit     4   4 3 3 3     3      
Crankshaft position sensor circuit 2 2                       DTC Description
Intake camshaft position sensor (PHASE) circuit 3 2                       DTC Description
Turbocharger boost sensor circuit     3   3                  
Manifold absolute pressure sensor circuit         2                  
Vehicle speed signal circuit   2 3   3           3     DTC Description
ECM 2 2 3 3 3 3 3 3 3 3 3     DTC Description
Electric Intake valve timing control module circuit     3   3 3                
Exhaust valve timing control solenoid valve circuit   3 2   1 3 2 2 3   3     DTC Description ,DTC Description
Electric Intake valve timing control actuator circuit         3                  
Exhaust camshaft position sensor circuit 5 5 5 5 5   5 5     5     DTC Description
Transmission range switch     3   3   3 3     3     DTC Description
Intake manifold runner control valve motor circuit 5 4 4 2 4   4 4     4      
Intake manifold runner control valve position sensor circuit                            
Turbocharger bypass control valve circuit     3   3                  
Electric wastegate valve circuit         1                  
Electric recircuration valve circuit         1                  
Refrigerant pressure sensor circuit   2       3     3   4     Component Function Check
Cooling fan control module circuit 5 5 5 5 5   5 5 5 4 5      
Battery current sensor circuit           4 5 5            
Electrical load signal circuit             3             Component Function Check
Air conditioner circuit 2 2 3 3 3 3 3 3 3   3   2 Work Flow
ABS actuator and electric unit (control unit)     4                     Work Flow
VCR System 5   1   2   3 4     6      

1 - 6: The numbers refer to the order of inspection.(continued on next table)

SYSTEM - ENGINE MECHANICAL and OTHER 

  SYMPTOM Reference
HARD/NO START/RESTART (EXCP. HA) ENGINE STALL HESITATION/SURGING/FLAT SPOT SPARK KNOCK/DETONATION LACK OF POWER/POOR ACCELERATION HIGH IDLE/LOW IDLE ROUGH IDLE/HUNTING IDLING VIBRATION SLOW/NO RETURN TO IDLE OVERHEATS/WATER TEMPERATURE HIGH EXCESSIVE FUEL CONSUMPTION EXCESSIVE OIL CONSUMPTION BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA  
Fuel Fuel tank 5 5                       Inspection
Fuel piping 5 5 5 5 5 5 Inspection
Vapor lock                         -
Valve deposit 5 5 5 5   5 5     5 -
Poor fuel (Heavy weight gasoline, Low octane)       -
Air Air duct   5 5   5   5 5     5     Inspection
Air cleaner Inspection
Air leakage from air duct (Mass air flow sensor - electric throttle control actuator) 5 5 5 5 Inspection
Electric throttle control actuator Exploded View
Air leakage from intake manifold/Collector/Gasket -
Cranking Battery 1 1 1   1   1 1     1   1 Work Flow
Generator circuit Work Flow (With 165- DSS-5000P) , Work Flow (Without 165- DSS-5000P)
Starter circuit 3             Work Flow (With 165- DSS-5000P) , Work Flow (Without 165- DSS-5000P)
Signal plate 6 Exploded View
Transmission range switch 4 Component Inspection
Engine Cylinder head 5 5 5 5 5   5 5     5     Inspection
Cylinder head gasket 4 3  
Cylinder block 6 6 6 6 6 6 6   6 4 Serviced as an assembly
Piston
Piston ring
Connecting rod  
Bearing
Crankshaft
Valve mechanism Timing chain 5 5 5 5 5   5 5     5     Inspection
Camshaft Inspection
Intake valve timing control Inspection
Exhaust valve timing control Inspection
Intake valve 3 Inspection
Exhaust valve
Exhaust Exhaust manifold/Tube/Muffler/Gasket 5 5 5 5 5   5 5     5     Inspection ,Inspection
Three way catalyst
Lubrication Oil pan/Oil strainer/Oil pump/Oil filter/Oil gallery/Oil cooler 5 5 5 5 5   5 5     5     Inspection ,Inspection ,Inspection
Oil level (Low)/Filthy oil Inspection
Variable displacement oil pump 5 5   4             4      
Cooling Radiator/Hose/Radiator filler cap 5 5 5 5 5   5 5   4 5     Inspection ,Inspection
Multi-way control valve 5 Component Inspection (Multi-way Control Valve)
Water pump   Inspection
Water gallery Engine Cooling System Schematic
Cooling fan 5 Exploded View
Coolant level (Low)/Contaminated coolant Inspection

1 - 6: The numbers refer to the order of inspection.