LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Infiniti >> 2024 >> QX80 Premium Select, AWD >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System (2 Of 2) >> Symptom Diagnosis >> Engine Control System >> Engine Control System Symptoms >> Symptom Table
April 5, 2026: LEMON Manuals is launched! Read the announcement.

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 Low pressure fuel pump circuit 1 1 2 3 2   2 2     3   2 Refer to Component Function Check .
Fuel pressure regulator system 3 3 4 4 4 4 4 4 4   4     Refer to Work Procedure .
Fuel injector circuit 1 1 2 3 2   2 2     2     Refer to Component Function Check .
Evaporative emission system 3 3 4 4 4 4 4 4 4   4     Refer to EVAP CANISTER : Periodic Maintenance .
FRP sensor circuit 1 1 2 2 2   2 2     2     Refer to DTC Description .
High pressure fuel pump circuit     4   3                 Refer to Component Function Check .
Air Positive crankcase ventilation system 3 3 4 4 4 4 4 4 4   4 1   Refer to POSITIVE CRANKCASE VENTILATION : Periodic Maintenance .
Incorrect idle speed adjustment       1 1 1 1   1     Refer to Work Procedure . Refer to Work Procedure .
Electric throttle control actuator 1 1 2 3 3 2 2 2 2   2   2 Refer to DTC Description . Refer to DTC Description .
Ignition Incorrect ignition timing adjustment 3 3 1 1 1   1 1     1     Refer to Work Procedure .
Ignition circuit 1 1 2 2 2   2 2     2     Refer to Component Function Check .
Main power supply and ground circuit 2 2 3 3 3   3 3   2 3     Refer to Diagnosis Procedure .
Mass air flow sensor circuit 1 1 2 2 2   2 2     2     Refer to DTC Description .
Engine coolant temperature sensor 1 circuit 3 3 3       Refer to DTC Description .
Air fuel ratio (A/F) sensor 1 circuit             Refer to DTC Description . Refer to DTC Description .
Throttle position sensor circuit     2 2       Refer to DTC Description .
Accelerator pedal position sensor circuit     3 2 1             Refer to DTC Description .
Knock sensor circuit     2               3     Refer to DTC Description . Refer to DTC Description .
Engine oil temperature sensor     4   2           3     Refer to DTC Description .
Engine oil pressure sensor     4   4 3 3 3     3     Refer to DTC Description .
Crankshaft position sensor circuit 2 2                       Refer to DTC Description .
Camshaft position sensor circuit 3 2                       Refer to DTC Description . Refer to DTC Description .
Vehicle speed signal circuit   2 3   3           3     Refer to DTC Description .
Power steering pressure sensor circuit   2         3 3           Refer to DTC Description .
ECM 2 2 3 3 3 3 3 3 3 3 3     -
Intake valve timing control solenoid valve circuit   3 2   1 3 2 2 3   3     Refer to DTC Description . Refer to DTC Description .
Exhaust valve timing control solenoid valve circuit   3 2   1 3 2 2 3   3     Refer to DTC Description . Refer to DTC Description .
Exhaust valve timing control position sensor 5 5 5 5 5   5 5     5     Refer to DTC Description . Refer to DTC Description .
Exhaust gas temperature sensor                     5     Refer to DTC Description .
VVEL control module 3   4 4 3                 Refer to Component Description .
VVEL actuator motor 3   4 4 3                 Refer to DTC Description . Refer to DTC Description .
VVEL actuator motor relay 3   4 4 3                 Refer to DTC Description .
VVEL control shaft position sensor 3   4 4 3                 Refer to DTC Description . Refer to DTC Description .
PNP signal circuit     3   3   3 3     3     Refer to DTC Description .
Refrigerant pressure sensor circuit   2       3     3   4     Refer to Component Function Check .
Electrical load signal circuit             3             Refer to Component Function Check .
Air conditioner circuit 2 2 3 3 3 3 3 3 3   3   2 Refer to Work Flow .
ABS actuator and electric unit (control unit)     4                     Refer to Work Flow .
Battery current sensor           4 5 5         3 Refer to DTC Description .
Heated oxygen sensor 2     6   6   6 6     5     Refer to DTC Description . Refer to DTC Description .

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

(continued on next page)

SYSTEM - ENGINE MECHANICAL and OTHER 

  SYMPTOM Reference page
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                       Refer to FUEL SYSTEM : Inspection .
Fuel piping 5 5 5 5 5 5 Refer to FUEL SYSTEM : Inspection . Refer to FUEL SYSTEM : 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     Refer to AIR CLEANER AND AIR DUCT : Inspection .
Air cleaner Refer to AIR CLEANER AND AIR DUCT : Exploded View .
Air leakage from air duct
(Mass air flow sensor - electric throttle control actuator)
5 5 5 5 Refer to AIR CLEANER AND AIR DUCT : Inspection .
Electric throttle control actuator Refer to DTC Description .
Air leakage from intake manifold/Collector/Gasket Refer to INTAKE MANIFOLD : Exploded View .
Cranking Battery 1 1 1   1   1 1     1   1 Refer to Work Flow .
Generator circuit Refer to Work Flow .
Starter circuit 3             Refer to Work Flow .
Signal plate 6 Refer to CYLINDER BLOCK : Exploded View .
PNP signal 4 Refer to DTC Description .
Engine Cylinder head 5 5 5 5 5   5 5     5     Refer to CYLINDER HEAD : Inspection .
Cylinder head gasket 4 3  
Cylinder block 6 6 6 6 6 6 6   6 4 Refer to CYLINDER BLOCK : Inspection .
Piston
Piston ring
Connecting rod  
Bearing
Crankshaft
Valve mechanism Timing chain 5 5 5 5 5   5 5     5     Refer to TIMING CHAIN : Inspection .
Camshaft Refer to CAMSHAFT : Inspection .
Intake valve timing control Refer to TIMING CHAIN : Exploded View .
Intake valve 3 Refer to CYLINDER HEAD : Inspection .
Exhaust valve
Exhaust Exhaust manifold/Tube/Muffler/Gasket 5 5 5 5 5   5 5     5     Refer to EXHAUST MANIFOLD AND THREE WAY CATALYST : Inspection . Refer to EXHAUST SYSTEM : Inspection (Removal and Installation) .
Three way catalyst
Lubrication Oil pan/Oil strainer/Oil pump/Oil filter/Oil gallery/Oil cooler 5 5 5 5 5   5 5     5     Refer to OIL PAN (LOWER) AND OIL STRAINER : Inspection . Refer to OIL PAN (UPPER) : Inspection . Refer to OIL FILTER : Inspection . Refer to OIL COOLER : Inspection . Refer to OIL PUMP : Inspection .
Oil level (Low)/Filthy oil Refer to ENGINE OIL : Inspection .
Cooling Radiator/Hose/Radiator filler cap 5 5 5 5 5   5 5   4 5     Refer to RESERVOIR TANK CAP : Inspection . Refer to RADIATOR : Inspection .
Water pump Refer to WATER PUMP : Inspection .
Water gallery Refer to WATER PUMP : Inspection .
Cooling fan 5 Refer to ENGINE COOLING FAN : Inspection .
Coolant level (Low)/Contaminated coolant Refer to ENGINE COOLANT : Inspection .
Multi-way control valve 4 Refer to MULTI-WAY CONTROL VALVE : Inspection .
IVIS (INFINITI Vehicle Immobilizer System - NATS) 1 1                       Refer to Work Flow .

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

* : For the details of the EXP-800 NI or GR8-1200 NI, Refer to SPECIAL SERVICE TOOL : Preparation .