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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 22 (Engine Mechanical System (A25A-FXS) - Service Information (1 Of 3)) >> Engine >> On-Vehicle Inspection [12/2019 - ] >> Procedure

On-Vehicle Inspection [12/2019 - ]: Procedure

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  1. INSPECT ENGINE COOLANT (for Engine) 

    Refer to ON-VEHICLE INSPECTION [12/2019 - ]

  2. INSPECT ENGINE OIL 

    Refer to ON-VEHICLE INSPECTION [12/2019 - 11/2023] , or refer to ON-VEHICLE INSPECTION [11/2023 - ]

  3. INSPECT AUXILIARY BATTERY 

    Refer to ON-VEHICLE INSPECTION [12/2019 - 11/2023] , or refer to ON-VEHICLE INSPECTION [11/2023 - ]

  4. INSPECT SPARK PLUG 

    Refer to ON-VEHICLE INSPECTION [12/2019 - ]

  5. INSPECT AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY 
    1. Remove the air cleaner filter element sub-assembly.
    2. Visually check that the air cleaner filter element sub-assembly is not damaged or excessively oily.

      HINT: 

      • If there is any dirt or clogs in the air cleaner filter element sub-assembly, clean it with compressed air.
      • If any dirt or clogs remain even after cleaning the air cleaner filter element sub-assembly with compressed air, replace it.
    3. Install the air cleaner filter element sub-assembly.
  6. INSPECT VALVE LASH ADJUSTER ASSEMBLY NOISE 
    1. Put the engine in inspection mode.

      Refer to INSPECTION MODE PROCEDURE [12/2019 - ]

    2. Rev up the engine several times. Check that the engine does not emit unusual noises.
    3. If unusual noises occur, warm up the engine and idle it for 30 minutes or more, then perform the inspection.

      HINT: 

      If any defects or problems are found during the inspection, perform valve lash adjuster assembly inspection.

      Refer to PROCEDURE - Step 2

  7. INSPECT IGNITION TIMING 
    NOTE:
    • Check the ignition timing with the cooling fan off.
    • Turn off all electrical systems and the A/C.
    • When checking the ignition timing, the transaxle should be in park.
    1. Put the engine in inspection mode.

      Refer to INSPECTION MODE PROCEDURE [12/2019 - ]

    2. Warm up and stop the engine.
    3. Put the engine in inspection mode.

      Refer to INSPECTION MODE PROCEDURE [12/2019 - ]

    4. Monitor Ignition Timing Cylinder #1 of the Data List.

      Powertrain > Engine > Data List 

      Tester Display
      Ignition Timing Cylinder #1

      Standard Ignition Timing

      -2 to 14° BTDC at idle

    5. Check that the ignition timing advances immediately when the engine speed is increased.
    6. Monitor Ignition Timing Cylinder #1 of the Data List.

      Powertrain > Engine > Active Test 

      Active Test Display
      Activate the TC Terminal
      Data List Display
      Ignition Timing Cylinder #1

      Standard Ignition Timing

      8 to 12° BTDC at idle

  8. INSPECT ENGINE IDLE SPEED 
    NOTE:
    • Check the engine idle speed with the cooling fan off.
    • Turn off all electrical systems and the A/C.
    • When checking the engine idle speed, the transaxle should be in park.
    1. Put the engine in inspection mode.

      Refer to INSPECTION MODE PROCEDURE [12/2019 - ]

    2. Warm up and stop the engine.
    3. Put the engine in inspection mode.

      Refer to INSPECTION MODE PROCEDURE [12/2019 - ]

    4. Read the value displayed on the GTS.

      Powertrain > Engine > Data List 

      Tester Display
      Engine Speed

      Standard Idle Speed

      1050 to 1150 rpm

  9. INSPECT COMPRESSION 
    NOTE:

    Keep the spark plug holes free of foreign matter when measuring the compression pressure.

    1. Put the engine in inspection mode.

      Refer to INSPECTION MODE PROCEDURE [12/2019 - ]

    2. Warm up and stop the engine.
    3. Check for DTCs.

      Refer to DTC CHECK / CLEAR [12/2019 - 10/2022] , or refer to DTC CHECK / CLEAR [10/2022 - 11/2023] , or refer to DTC CHECK / CLEAR [11/2023 - ]

    4. Remove the front wheel opening extension pad LH.

      See step  7[12/2019 - 10/2022], or refer to PROCEDURE - Step 7 [10/2022 - 11/2023] , or refer to PROCEDURE - Step 7 [11/2023 - ]

    5. Remove the front wheel opening extension pad RH.

      See step  8[12/2019 - 10/2022], or refer to PROCEDURE - Step 8 [10/2022 - 11/2023] , or refer to PROCEDURE - Step 8 [11/2023 - ]

    6. Remove the No. 1 engine under cover.

      See step  9[12/2019 - 10/2022], or refer to PROCEDURE - Step 9 [10/2022 - 11/2023] , or refer to PROCEDURE - Step 9 [11/2023 - ]

    7. Remove the cool air intake dust seal.

      Refer to PROCEDURE - Step 1 [12/2019 - 09/2020] , or refer to PROCEDURE - Step 1 [09/2020 - 11/2023] , or refer to PROCEDURE - Step 1 [11/2023 - ]

    8. Remove the intake air cleaner assembly.

      Refer to PROCEDURE - Step 6 [12/2019 - 10/2022] , or refer to PROCEDURE - Step 6 [10/2022 - 11/2023] , or refer to PROCEDURE - Step 6 [11/2023 - ]

    9. Remove the air cleaner cap with air cleaner hose.

      Refer to PROCEDURE - Step 5 [12/2019 - 09/2020] , or refer to PROCEDURE - Step 5 [09/2020 - ]

    10. Disconnect the fuel injector connector (for Port Injection).
      GTY761415Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    11. Disengage the claw and raise the lock lever to disconnect the No. 6 engine wire connector as shown in the illustration.
      GTY869403Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Lock Lever
      NOTE:

      Perform this step in order to stop fuel injection and prevent damage to the catalyst due to unburned fuel.

    12. Remove the 4 spark plugs.

      Refer to REMOVAL [12/2019 - ]

      NOTE:

      DTCs will be stored if the inspection is performed with the ignition coil assembly connectors disconnected. Make sure that the ignition coil assembly connectors are connected during the inspection.

    13. Check the cylinder compression pressure.
      1. Insert a compression gauge into the spark plug hole.
        GTY766717Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      2. Depress and hold the brake pedal, and turn the ignition switch to ON (READY). Then check the compression pressure.

        Powertrain > Hybrid Control > Active Test 

        Tester Display
        Compression Test

        Standard Compression Pressure

        870 kPa (8.9 kgf/cm 2 , 126 psi)

        Minimum Compression Pressure

        700 kPa (7.1 kgf/cm 2 , 102 psi)

        Pressure Difference between Each Cylinder

        200 kPa (2.0 kgf/cm 2 , 29 psi) or less

        NOTE:
        • Check the HV battery voltage in the Data List to ensure that the auxiliary battery is fully charged.
        • Noise may be emitted from the hybrid vehicle transaxle assembly. However, this is not a malfunction.
        • Inspect all cylinders in the same way.
        • Measure the compression pressure as quickly as possible.
      3. If the cylinder compression pressure is low, pour a small amount of engine oil into the cylinder through the spark plug hole and inspect it again.

        HINT: 

        • If adding oil increases the compression pressure, the piston rings and/or cylinder bore may be worn or damaged.
        • If the compression pressure stays low, a valve may be stuck or seated improperly, or there may be leaks in the cylinder head gasket.
    14. Install the 4 spark plugs.

      Refer to INSTALLATION [12/2019 - ]

    15. Install the air cleaner cap with air cleaner hose.

      Refer to PROCEDURE - Step 3 [12/2019 - 09/2020] , or refer to PROCEDURE - Step 3 [09/2020 - ]

    16. Install the inlet air cleaner assembly.

      Refer to PROCEDURE - Step 20 [12/2019 - 11/2023] , or refer to PROCEDURE - Step 20 [11/2023 - ]

    17. Install the cool air intake dust seal.

      Refer to PROCEDURE - Step 4 [12/2019 - 09/2020] , or refer to PROCEDURE - Step 4 [09/2020 - ]

    18. Connect the No. 6 engine wire connector and push down the lock lever to engage the claw as shown in the illustration.
      GTY765620Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Lock Lever
    19. Connect the fuel injector connector (for Port Injection).
      GTY761415Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    20. Install the No. 1 engine under cover.

      Refer to PROCEDURE - Step 63 [12/2019 - 10/2022] , or refer to PROCEDURE - Step 63 [10/2022 - 11/2023] , or refer to PROCEDURE - Step 61 [11/2023 - ]

    21. Install the front wheel opening extension pad LH.

      Refer to PROCEDURE - Step 64 [12/2019 - 10/2022] , or refer to PROCEDURE - Step 64 [10/2022 - 11/2023] , or refer to PROCEDURE - Step 62 [11/2023 - ]

    22. Install the front wheel opening extension pad RH.

      Refer to PROCEDURE - Step 65 [12/2019 - 10/2022] , or refer to PROCEDURE - Step 65 [10/2022 - 11/2023] , or refer to PROCEDURE - Step 63 [11/2023 - ]

    23. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [12/2019 - 10/2022] , or refer to DTC CHECK / CLEAR [10/2022 - 11/2023] , or refer to DTC CHECK / CLEAR [11/2023 - ]

      NOTE:

      After performing the inspection, clear the DTCs and confirm that DTCs are not stored again or that the normal system code is output if using a check wire.

  10. INSPECT CO/HC 

    HINT: 

    This check determines whether or not the idle CO/HC complies with regulations.

    1. Put the engine in inspection mode.

      Refer to INSPECTION MODE PROCEDURE [12/2019 - ]

    2. Run the engine speed at 2500 rpm for approximately 180 seconds.
    3. Insert a CO/HC meter testing probe at least 40 cm (1.31 ft.) into the tailpipe during idle.
    4. Immediately check the CO/HC concentration at idle and then at an engine speed of 2500 rpm.

      HINT: 

      When performing a 2 mode test (with the engine idling/running at 2500 rpm), the measurement procedures are determined by applicable local regulations.

      If the CO/HC concentration does not comply with the regulations, perform troubleshooting in the order given below.

      1. Check for DTCs.

        Refer to DTC CHECK / CLEAR [12/2019 - 10/2022] , or refer to DTC CHECK / CLEAR [10/2022 - 11/2023] , or refer to DTC CHECK / CLEAR [11/2023 - ]

      2. See the following table for possible causes, then inspect the applicable parts and repair them if necessary.
        CO HC Problem Cause
        Normal High Rough idle
        1. Faulty ignition:
          • Incorrect valve timing
          • Fouled, shorted or improperly gapped spark plugs
        2. Incorrect valve clearance (valve lash adjuster assembly)
        3. Leaks in intake or exhaust valves
        4. Leaks in cylinders
        5. Faulty EGR
        Low High Rough idle (Fluctuating HC reading)
        1. Vacuum leaks:
          • PCV hoses
          • Intake manifold
          • Throttle body with motor assembly
        2. Lean mixture causing misfire
        3. Faulty EGR
        High High Rough idle (Black smoke from exhaust)
        1. Restricted air cleaner filter element sub-assembly
        2. Plugged PCV valve
        3. Faulty SFI systems:
          • Fuel pressure regulator assembly
          • Engine coolant temperature sensor
          • Mass air flow meter sub-assembly
          • ECM
          • Fuel injector assemblies
          • Throttle position sensor (built into throttle body with motor assembly)
        4. Faulty EGR
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