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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 39 (Hybrid Control System (AWD) - Diagnostics - Introduction (1 Of 2)) >> HYBRID CONTROL SYSTEM (for AWD) >> Problem Symptoms Table [12/2019 - 10/2022] >> Problem Symptoms Table [12/2019 - 10/2022]

Problem Symptoms Table [12/2019 - 10/2022]

WARNING: This page is about a different variant/trim than selected.
HYBRID CONTROL SYSTEM

Symptom Suspected Area Link
Cannot enter EV mode CAN Communication System Refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - 10/2021] , or refer to HOW TO PROCEED WITH TROUBLESHOOTING [10/2021 - 10/2022]
Pattern Select Switch EV Mode Circuit Refer to Pattern Select Switch EV Mode Circuit [12/2019 - 11/2023]
EV drive mode switch (Pattern select switch assembly) Refer to INSPECTION [12/2019 - ]
Combination meter assembly Refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ]
EV mode indicator light does not illuminate Combination meter assembly Refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ]
EV drive mode switch (Pattern select switch assembly) Refer to INSPECTION [12/2019 - ]
Pattern Select Switch EV Mode Circuit Refer to Pattern Select Switch EV Mode Circuit [12/2019 - 11/2023]
EV mode indicator light does not turn off Combination meter assembly Refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ]
EV drive mode switch (Pattern select switch assembly) Refer to INSPECTION [12/2019 - ]
Pattern Select Switch EV Mode Circuit Refer to Pattern Select Switch EV Mode Circuit [12/2019 - 11/2023]
Cannot enter Sport/Eco mode CAN Communication System Refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - 10/2021] , or refer to HOW TO PROCEED WITH TROUBLESHOOTING [10/2021 - 10/2022]
Drive mode select switch (No. 1 pattern select switch assembly) Refer to INSPECTION [12/2019 - ]
Drive Mode Select Switch Circuit Refer to Drive Mode Select Switch Circuit [12/2019 - 11/2023]
Combination meter assembly Refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ]
Sport/Eco mode indicator light does not illuminate Drive mode select switch (No. 1 pattern select switch assembly) Refer to INSPECTION [12/2019 - ]
Drive Mode Select Switch Circuit Refer to Drive Mode Select Switch Circuit [12/2019 - 11/2023]
Combination meter assembly Refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ]
Sport/Eco mode indicator light does not turn off Drive mode select switch (No. 1 pattern select switch assembly) Refer to INSPECTION [12/2019 - ]
Drive Mode Select Switch Circuit Refer to Drive Mode Select Switch Circuit [12/2019 - 11/2023]
Combination meter assembly Refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ]
Cannot enter TRAIL mode CAN Communication System Refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - 10/2021] , or refer to HOW TO PROCEED WITH TROUBLESHOOTING [10/2021 - 10/2022]
TRAIL mode switch (Pattern select switch) Refer to INSPECTION [12/2019 - ]
TRAIL Switch Circuit Refer to TRAIL Switch Circuit [12/2019 - 11/2023]
Combination meter assembly Refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ]
TRAIL indicator does not illuminate TRAIL mode switch (Pattern select switch) Refer to INSPECTION [12/2019 - ]
TRAIL Switch Circuit Refer to TRAIL Switch Circuit [12/2019 - 11/2023]
Combination meter assembly Refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ]
TRAIL indicator does not turn off TRAIL mode switch (Pattern select switch) Refer to INSPECTION [12/2019 - ]
TRAIL Switch Circuit Refer to TRAIL Switch Circuit [12/2019 - 11/2023]
Combination meter assembly Refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ]
Hunting (Poor idle) Check for Diagnosis Related Information*3 Refer to UTILITY [12/2019 - 11/2023] 
Refer to UTILITY [12/2019 - 11/2023]
Drive Start Control Refer to Drive Start Control [12/2019 - 10/2022]
Hesitation and/or poor acceleration Check for Diagnosis Related Information*3 Refer to UTILITY [12/2019 - 11/2023] 
Refer to UTILITY [12/2019 - 11/2023]
Brake Override System Refer to Brake Override System [12/2019 - 10/2022]
Drive Start Control Refer to Drive Start Control [12/2019 - 10/2022]
Shift range position cannot be changed by shifting to "+" or "-" Transmission Control Switch Circuit Refer to Transmission Control Switch Circuit [12/2019 - 11/2023]
Shift position indicator is malfunctioning Indicator circuit Refer to Indicator Circuit [12/2019 - 11/2023]
Ignition switch does not turn ON (READY) Check Vehicle Control History (wrong assembly confirmation)*1 Refer to REMOVAL [12/2019 - 10/2022]
Smart Key System (for Start Function) Refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - 10/2021] , or refer to HOW TO PROCEED WITH TROUBLESHOOTING [10/2021 - 11/2023]
ECU Power Source Circuit (Hybrid Control System) Refer to ECU Power Source Circuit [12/2019 - 11/2023]
Hybrid vehicle control ECU Refer to REMOVAL [12/2019 - 10/2022]
ECM Refer to REMOVAL [12/2019 - 10/2022]
Loud rattle from hybrid vehicle transaxle Check idle learning Refer to INITIALIZATION [12/2019 - 10/2021] , or refer to INITIALIZATION [10/2021 - ]
Transmission input damper assembly Refer to REMOVAL [12/2019 - 10/2022]
Hybrid vehicle transaxle assembly Refer to REMOVAL [12/2019 - 10/2022]
Engine misfire -
"Maintenance Required for Traction Battery Cooling Parts See Owner's Manual" is displayed on the multi-information display.*2 1. Make sure the HV battery cooling system intake port is not blocked. -
2. Make sure there are no gaps between the connecting parts of the ducts. -
3. Clean the No. 2 hybrid battery intake filter.
Check for entry of foreign matter.
Refer to INSPECTION [12/2019 - ]
4. Clear the DTCs to reset the learning values even if no DTCs are stored. Refer to DTC CHECK / CLEAR [12/2019 - 11/2023] 
Abnormal sound is heard from the area around the No. 1 hybrid battery intake duct. 1. Make sure the HV battery cooling system intake port is not blocked. -
2. Make sure there are no gaps between the connecting parts of the ducts. -
3. Clean the No. 2 hybrid battery intake filter.
Check for entry of foreign matter.
Refer to INSPECTION [12/2019 - ]
4. Clear the DTCs to reset the learning values even if no DTCs are stored. Refer to DTC CHECK / CLEAR [12/2019 - 11/2023] 
Engine stops and starts less frequently. Check Vehicle Control History
(Limit to Charge / Discharge Control Value by Hybrid Battery Temperature High)
Refer to VEHICLE CONTROL HISTORY [12/2019 - 11/2023]
Engine speed returns to idle slowly after accelerator pedal is fully released. Check Vehicle Control History
(Limit to Charge / Discharge Control Value by Hybrid Battery Temperature High)
Refer to VEHICLE CONTROL HISTORY [12/2019 - 11/2023]

*1: Check Vehicle Control History (wrong assembly confirmation)

  1. Using the GTS, check the Vehicle Control History.

    Refer to VEHICLE CONTROL HISTORY [12/2019 - 11/2023]

    HINT: 

    If "Hybrid Battery Pack Sensor Module Mismatch" is displayed, the wrong type of battery voltage sensor is installed.

  2. If the battery voltage sensor had been replaced just before the malfunction occurred, check the part number of the battery voltage sensor.

    HINT: 

    • The type of battery voltage sensor to be used varies depending on the vehicle model.
    • If the wrong type of battery voltage sensor is installed, the ignition switch cannot be turned to ON (READY).
  3. After installing the battery voltage sensor, perform the following to check that the ignition switch can be turned to ON (READY).
    1. Turn the ignition switch to ON (READY).
    2. Turn the ignition switch off and wait for 2 minutes or more.
    3. Turn the ignition switch to ON (READY) again.

*2: If the battery cooling blower assembly malfunctions, DTC P0A81-00, P0A81-11, P0A81-15, P0A81-4B, P0A81-96, P0A81-98, P0A96-00, P0A96-11, P0A96-15, P0A96-4B, P0A96-96 or P0A96-98 will be stored. If only "Maintenance Required for Traction Battery Cooling Parts See Owner's Manual" is displayed on the multi-information display, only perform the inspection of the HV battery cooling system intake port, filter and duct.

*3: If any of the following Diagnosis Related Information items are output, perform troubleshooting for the corresponding DTCs.

RESULT

Result Link
Hybrid Control System P3123-87 Refer to DTC P3123-87: Lost Communication with Drive Motor Control Module "A" from Hybrid/EV Control Module Missing Message [12/2019 - 11/2023]
Motor Generator Control System P3124-1F Refer to DTC P3124-1F: Lost Communication between Drive Motor "A" and HV ECU Circuit Intermittent; DTC P3124-87: Lost Communication between Drive Motor "A" and HV ECU Missing Message [12/2019 - 11/2023]
P3124-87