Toyota Yaris: Sfi System / Rough Idling

• Mass Air Flow Sensor
• 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 Pump2 Duty Ratio (D4)
• High Pressure Fuel Pump Discharge Rate
• High Pressure Fuel Pump2 Discharge Rate
• Target Air-Fuel Ratio
• A/F (O2) Sensor Current B1S1
• A/F (O2) Sensor Current B1S2
• Short FT B1S1
• Long FT B1S1
• Total FT Bank 1
• Fuel System Status Bank 1
• A/F Learn Value Idle Bank 1
• A/F Learn Value Low Bank 1
• A/F Learn Value Mid No.1 Bank 1
• A/F Learn Value Mid No.2 Bank 1
• A/F Learn Value High Bank 1
• A/F Learn Value Idle (Port) Bank 1
• A/F Learn Value Low (Port) Bank 1
• A/F Learn Value Mid No.1 (Port) Bank 1
• A/F Learn Value Mid No.2 (Port) Bank 1
• A/F Learn Value High (Port) Bank 1
• Misfire Count Cylinder #1 to #3
• Compression Leakage Count
• Rough Idle Status
• Plural Cylinders Rough Idle
• Rough Idle Cylinder #1 to #3

• Rough Idle Count (Plural Cylinders)
• Rough Idle Count (Compression Leakage)
• Rough Idle Count (Low Frequency)
• Rough Idle Count #1 to #3

HINT:

• If any other DTCs are output, perform troubleshooting for those DTCs first.
• Make sure to reproduce the conditions present when the malfunction occurred.
• Using the GTS, read the Data List to confirm the engine operating conditions. This information can be useful when troubleshooting.
• The vehicle condition when the problem symptoms occurred can be determined using the Vehicle Control History.
• As the Vehicle Control History data may be overwritten whenever the trigger conditions are met, make sure to save the Vehicle Control History data before performing any inspections.
• If the problem symptoms do not recur, attempt to reproduce the symptoms and conditions when the malfunction occurred based on the result of the customer problem analysis and Vehicle Control History. Place the priority on confirming the symptoms.
• When performing inspections, jiggle the relevant wire harnesses and connectors in an attempt to reproduce malfunctions that do not always occur.
• The suspected cause of the problem symptoms can be determined using the codes, items, and Freeze Frame Data within the Vehicle Control History.
• When confirming the Freeze Frame Data, be sure to check all multi Freeze Frame Data.
• When confirming the Freeze Frame Data, if there are multiple items related to the cause of the malfunction, perform troubleshooting for all related items.
• If the malfunction is currently occurring, use the Data List to confirm the current vehicle condition. By using the Data List, more detailed vehicle information can be confirmed than by using Vehicle Control History Freeze Frame Data by itself.
• As Vehicle Control History may be stored when performing an Active Test, learning, etc., make sure to clear the Vehicle Control History before returning the vehicle to the customer.

HINT:

• "Total FT Bank 1" is used to detect an abnormal air fuel ratio. As the value of "Total FT Bank 1" is corrected by the ECM before it is displayed in the Data List, the displayed value may not be equal to the sum of the measured "Short FT B1S1" and "Long FT B1S1".
• An abnormally lean or rich tendency can be checked by reading the following Data List items: A/F Learn Value Idle Bank 1, A/F Learn Value Low Bank 1, A/F Learn Value Mid No.1 Bank 1, A/F Learn Value Mid No.2 Bank 1, A/F Learn Value High Bank 1, A/F Learn Value Idle (Port) Bank 1, A/F Learn Value Low (Port) Bank 1, A/F Learn Value Mid No.1 (Port) Bank 1, A/F Learn Value Mid No.2 (Port) Bank 1 and A/F Learn Value High (Port) Bank 1.
• The following may cause a lean air fuel ratio (an operating range in which the air fuel ratio learned value correction is +20% or more):
  1. Decrease in fuel injector assembly injection volume
  2. Decrease in mass air flow meter sub-assembly output (due to existence of foreign matter)
  3. Air leaks in intake system after mass air flow meter sub-assembly
  4. Decrease in fuel pressure (at fuel filter, fuel pump, fuel main valve assembly or fuel suction plate sub-assembly)
• On vehicles which the learning value for each operating range can be checked, if the value of "A/F Learn Value High Bank 1" or "A/F Learn Value High (Port) Bank 1" only is corrected to the positive side, a malfunction in the fuel system (clogging of the fuel pump or fuel filter) is suspected.
• On vehicles which the learning value for each operating range can be checked, if the value of "A/F Learn Value Idle Bank 1", "A/F Learn Value Low Bank 1", "A/F Learn Value Idle (Port) Bank 1" or "A/F Learn Value Low (Port) Bank 1" only is corrected to the positive side, an air leak after the mass air flow meter sub-assembly is suspected.
• The following may cause a rich air fuel ratio (an operating range in which the air fuel ratio learned value correction is -20% or less):
  1. Increase in the fuel injector assembly injection volume
  2. Purge VSV system

HINT:

• Perform fuel-cut of port injection and direct injection for each cylinder and check the change in the engine speed.
• If the engine speed of a cylinder does not change while performing the Active Test, it can be determined that the cylinder is malfunctioning.
• If the engine speed of all cylinders change while performing the Active Test, it can be determined that multiple cylinders are malfunctioning.
• A cylinder for which the Data List item "Misfire Count Cylinder #1 to #3" increases may be malfunctioning.
• If "Compression Leakage Count" in the Data List increases, misfiring due to insufficient compression may be occurring.

NOTICE:

• Do not crank the engine continuously for 20 seconds or more.
• If it is necessary to crank the engine again after Check the Cylinder Compression has been changed to "Start" and the engine has been cranked once, press Exit to return to the Active Test menu screen. Then change Check the Cylinder Compression to "Start" and crank the engine.
• Make sure the auxiliary battery is fully charged before performing this Active Test.

NOTICE:

• If the Active Test is changed to "Stop" while the engine is being cranked, the engine will start.
• When performing the Active Test, Vehicle Control History code X0810 (Engine Difficult to Start (Engine Starting Time Long)) may be stored.
• After performing the Active Test, make sure to check and clear DTCs.

HINT:

• At first, the GTS will display extremely high cylinder engine speed values. After approximately 10 seconds of engine cranking, the engine speed measurement of each cylinder will change to the actual engine speed.
• If the value of Data List item "Engine Speed Cylinder" of a cylinder is higher than other cylinders, the cylinder may be malfunctioning.
• If the value of Data List item "Engine Speed Cylinder" is high for only one cylinder, compression loss is suspected.

HINT:

• Increase and decrease the fuel injection volume of the port injection and direct injection simultaneously and check the vehicle condition.
• Change the fuel injection volume between the minimum and maximum range of correction (e.g. -12.5% to 24.8%).

HINT:

• Interchange the ignition coil assembly and spark plug of the malfunctioning cylinder with those of a known good cylinder and check if the malfunctioning cylinder returns to normal.
• If the spark plug of the malfunctioning cylinder is abnormally wet with fuel even after the ignition coil assembly and spark plug are replaced, a leaking fuel injector assembly is suspected.

HINT:

• If the air fuel ratio learned value is corrected to the positive side for all operating ranges due to low fuel injector assembly injection volume, replace the fuel injector assemblies of all cylinders.
• Perform "Inspection After Repair" after replacing the fuel injector assembly.

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NOTICE:

• The air fuel ratio sensor (sensor 1) has an output delay of a few seconds and the air fuel ratio sensor (sensor 2) has a maximum output delay of approximately 20 seconds.
• Read the output current immediately after warming up the air fuel ratio sensors to avoid an inaccurate reading due to a sensor cooling.

HINT:

• Increase and decrease the fuel injection volume of the port injection and direct injection simultaneously and check the vehicle condition.
• Change the fuel injection volume between -12 to 12%.

• Engine mount deterioration
• Deposits in the intake manifold or on an intake valve
• Delay in fuel supply due to adherence of the fuel to the deposits

HINT:

• If there is foreign matter in the intake system components, remove it before proceeding to the next step.
• If there is no foreign matter in the intake system components, check for foreign matter in the mass air flow meter sub-assembly. If there is foreign matter in the mass air flow meter sub-assembly, remove it.

NOTICE:

• Make sure that the cloth or your fingers do not get caught in the valve.
• Make sure that foreign matter does not enter the throttle valve.
• Do not directly apply non-residue solvent to the throttle body with motor assembly or wash the throttle body with motor assembly. Cleaning solvent may leak into the motor from the shaft and cause problems such as rust or valve movement problems.
• If there is coating material on the edge of the valve, be careful not to remove it.

HINT:

• The illustrations are for reference only. Actual parts may differ.
• When cleaning or replacing one throttle body with motor assembly, clean the other throttle body with motor assembly.

Ignition Circuit

DESCRIPTION A direct ignition system is used on this vehicle. The direct ignition system is a 1 cylinder ignition system which ignites one cylinder with one ignition coil...

Engine Difficult to Start

DESCRIPTION Problem Symptom Suspected Area Trouble Area Engine does not crank Engine cranks slowly Auxiliary battery depletion Starter malfunction Starter system Auxiliary battery depletion Starter malfunction Starter circuit Excessive engine friction Engine Engine assembly Starting time is long Engine speed fluctuation due to abnormal combustion Idle speed too low or high The engine stalls immediately after starting Strong engine vibration due to above symptoms Ignition malfunction Deviation in air fuel ratio (Excessive or insufficient intake air volume or fuel supply) Insufficient compression Changes in load from another system Ignition system Spark plug Ignition coil assembly Fuel system Direct fuel injector assembly Port fuel injector assembly Fuel pump assembly (for high pressure side) Fuel pump (for low pressure side) Fuel pump control circuit Fuel suction plate sub-assembly Fuel main valve assembly Fuel line Purge VSV system Fuel quality (existence of foreign matter, degradation) Intake and exhaust systems Mass air flow meter sub-assembly Intake system (Air leaks or deposit accumulation) Throttle body with motor assembly Air fuel ratio sensor (sensor 1) Air fuel ratio sensor (sensor 2) Cam timing oil control solenoid assembly Variable Valve Timing system (VVT system) Other control systems ECM Wire harness or connector Knock control sensor Engine coolant temperature sensor Immobiliser system Engine Water control valve Engine assembly Crankshaft position sensor High load from another system Air conditioning system Power steering system Electrical load signal system SYMPTOM AND CAUSE OF SYSTEM MALFUNCTION HINT: The following are descriptions of the characteristics of each system malfunction...

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