Engine Stalls [12/2021 - ]: Description

HINT: 

The following are descriptions of the characteristics of each system malfunction. After understanding the link between the causes and symptoms, perform the inspection of each component. Even if the problem symptom does not recur, signs of the malfunction may be found in the Data List.

1. Ignition system
   SPARK PLUG
   
   

   Main cause of malfunction	Performance degradation (wear, existence of foreign matter, etc.)
   Symptom	Engine speed fluctuation due to abnormal combustion
   Data List	Misfire Count Cylinder #1 to #6
   HINT:  If the spark plug of the malfunctioning cylinder is abnormally wet with fuel, a leaking fuel injector assembly is suspected.

   IGNITION COIL ASSEMBLY
   
   

   Main cause of malfunction	Internal malfunction
   Problem symptom	Engine speed fluctuation due to abnormal combustion
   Data List	Misfire Count Cylinder #1 to #6

2. Fuel system
   FUEL INJECTOR ASSEMBLY
   
   

   Main cause of malfunction	Blockage
   Problem symptom	Engine speed fluctuation due to abnormal combustion Idle speed too low or high
   Data List	Target Air-Fuel Ratio Short FT B1S1, B2S1 Long FT B1S1, B2S1 Total FT Bank 1, Bank 2 Fuel System Status Bank 1, Bank 2 A/F Learn Value Idle Bank 1, Bank 2 A/F Learn Value Low Bank 1, Bank 2 A/F Learn Value Mid No. 1 Bank 1, Bank 2 A/F Learn Value Mid No. 2 Bank 1, Bank 2 A/F Learn Value High Bank 1, Bank 2 A/F Learn Value Idle (Port) Bank 1, Bank 2 A/F Learn Value Low (Port) Bank 1, Bank 2 A/F Learn Value Mid No. 1 (Port) Bank 1, Bank 2 A/F Learn Value Mid No. 2 (Port) Bank 1, Bank 2 A/F Learn Value High (Port) Bank 1, Bank 2
   HINT:  If the engine malfunction disappears when the fuel injection volume is increased or decreased using the "Control the Injection Volume", the respective cylinder may be malfunctioning.

   PURGE VSV
   
   

   Main cause of malfunction	Purge VSV stuck open
   Symptom	Engine speed fluctuation due to abnormal combustion
   Data List	EVAP (Purge) VSV Evap Purge Flow EVAP Purge Density Learn Value EVAP Purge VSV Purge Cut VSV Duty

   FUEL SYSTEM
   
   

   HINT:  If the air fuel ratio becomes lean only when the engine is running under a high load and at a high engine speed, clogging of the fuel pump assembly or fuel filter is suspected.

   FUEL QUALITY
   
   

   Main cause of malfunction	Fuel degradation due to age or water contamination Low fuel quality Addition of fuel additive
   Problem symptom	Engine speed fluctuation due to abnormal combustion Idle speed too low or high Engine is difficult to start Lack of power

3. Intake and exhaust systems
   MASS AIR FLOW METER SUB-ASSEMBLY
   
   

   Main cause of malfunction	Performance degradation (existence of foreign matter, etc.)
   Problem symptom	Lack of power
   Data List	MAF Sensor Bank1, Bank 2
   HINT:  If the value of the Data List item "MAF Sensor Bank1, Bank 2" is abnormal, a malfunction of the mass air flow meter sub-assembly is suspected.

   THROTTLE SYSTEM
   
   

   Main cause of malfunction	Inappropriate trim volume adjustment due to accumulation of deposits
   Problem symptom	Engine speed fluctuation due to abnormal combustion Idle speed too low or high Lack of power
   Data List	Engine Stall Control F/B Flow ISC F/B Learn Torque ISC Total AUXS Torque ISC F/B Torque Sum of ISC F/B Torque (Recent) ISC AUXS Torque (Alternator) ISC AUXS Torque (Air Conditioner) Throttle Air Flow F/B Value

   AIR FUEL RATIO SENSOR (SENSOR 1), AIR FUEL RATIO SENSOR (SENSOR 2)
   
   

   Main cause of malfunction	Deviation in sensor characteristics
   Problem symptom	Abnormal combustion due to deviation of actual air fuel ratio from calculated ratio
   Data List	A/F (O2) Sensor Current B1S1, B2S1 A/F (O2) Sensor Current B1S2, B2S2 Fuel System Status Bank 1, Bank 2

4. Engine
   ENGINE ASSEMBLY
   
   

   Main cause of malfunction	Compression loss Accumulation of deposits (Combustion chamber, intake valve, exhaust valve or intake manifold)
   Problem symptom	Engine speed fluctuation due to abnormal combustion Idle speed too low or high Hesitation during acceleration or stalling
   Data List	Compression Leakage Count Rough Idle Status Plural Cylinders Rough Idle Rough Idle Cylinder #1 to #6
   HINT:  If deposits have accumulated in the combustion chamber or on an intake or exhaust valve, the engine may stall when deposits are caught on an intake or exhaust valve. When performing the Active Test "Check the Cylinder Compression", if the speed of one cylinder is higher than the others, the cylinder may have a compression loss. If deposits accumulate on the intake or exhaust valves, the supply of fuel may be delayed due to adherence of the fuel to the deposits, causing a rough idle.

   VVT
   
   

   Main cause of malfunction	Cam timing oil control solenoid assembly stuck open
   Symptom	Abnormal combustion due to excessive valve overlap
   Data List	VVT Advance Fail Exhaust VVT Retarded Fail Intake VVT Hold Learn Value Bank 1, Bank 2 Intake VVT OCV Control Duty Ratio Bank 1, Bank 2 Intake VVT Change Angle Bank 1, Bank 2 Exhaust VVT Hold Learn Value Bank 1, Bank 2 Exhaust VVT Change Angle Bank 1, Bank 2 Exhaust VVT OCV Control Duty Ratio Bank 1, Bank 2 Intake VVT Target Angle Bank 1, Bank 2 Exhaust VVT Target Angle Bank 1, Bank 2 Intake VVT Timing Most Over-Retarded Learn Value Bank 1, Bank 2 Exhaust VVT Timing Most Over-Advanced Learn Value Bank 1, Bank 2

HINT: 

Depending on the vehicle model, the applicable Data List items may vary. Data List items other than the ones used in the diagnostic procedure are for reference only.

• MAF Sensor Bank1, Bank 2
• Engine Stall Control F/B Flow
• ISC F/B Learn Torque
• ISC Total AUXS Torque
• ISC F/B Torque
• Sum of ISC F/B Torque (Recent)
• ISC AUXS Torque (Alternator)
• ISC AUXS Torque (Air Conditioner)
• Throttle Air Flow F/B Value
• Target Fuel Pressure (High)
• Target Fuel Pressure (Low) / Target Fuel Pressure 2
• Fuel Pressure (High)
• Fuel Pressure (Low) / Fuel Pressure 2
• High Pressure Fuel Pump Duty Ratio (D4)
• High Pressure Fuel Pump Discharge Rate
• Target Air-Fuel Ratio
• A/F (O2) Sensor Current B1S1, B2S1
• A/F (O2) Sensor Current B1S2, B2S2
• Short FT B1S1, B2S1
• Long FT B1S1, B2S1
• Total FT Bank 1, Bank 2
• Fuel System Status Bank 1, Bank 2
• A/F Learn Value Idle Bank 1, Bank 2
• A/F Learn Value Low Bank 1, Bank 2
• A/F Learn Value Mid No. 1 Bank 1, Bank 2
• A/F Learn Value Mid No. 2 Bank 1, Bank 2
• A/F Learn Value High Bank 1, Bank 2
• A/F Learn Value Idle (Port) Bank 1, Bank 2
• A/F Learn Value Low (Port) Bank 1, Bank 2
• A/F Learn Value Mid No. 1 (Port) Bank 1, Bank 2
• A/F Learn Value Mid No. 2 (Port) Bank 1, Bank 2
• A/F Learn Value High (Port) Bank 1, Bank 2
• VVT Advance Fail
• Exhaust VVT Retarded Fail
• Intake VVT Hold Learn Value Bank 1, Bank 2
• Intake VVT OCV Control Duty Ratio Bank 1, Bank 2
• Intake VVT Change Angle Bank 1, Bank 2
• Exhaust VVT Hold Learn Value Bank 1, Bank 2
• Exhaust VVT Change Angle Bank 1, Bank 2
• Exhaust VVT OCV Control Duty Ratio Bank 1, Bank 2
• Intake VVT Target Angle Bank 1, Bank 2
• Exhaust VVT Target Angle Bank 1, Bank 2
• Intake VVT Timing Most Over-Retarded Learn Value Bank 1, Bank 2
• Exhaust VVT Timing Most Over-Advanced Learn Value Bank 1, Bank 2
• Misfire Count Cylinder #1 to #6

HINT: 

The frequency of the malfunction can be determined by confirming the number of times the symptom occurred.

• Engine Stall Count
• Engine Stall Count (Compression Leakage)