Home/Lexus/CT/Lexus CT I (2010-2014)/Repair manual/Door Locks & Anti-Theft Systems/Smart Access System (Keyless Entry) (Diagnostic Codes & Sym…
Contents Wiring diagrams Section: Door Locks & Anti-Theft Systems All sections

Smart Access System (Keyless Entry) (Diagnostic Codes & Symptom Tests): Overview Lexus CT I

Door Locks & Anti-Theft Systems 17 illustrations ~2041 words

DESCRIPTION

The certification ECU (smart key ECU assembly) generates a request signal and transmits the signal to the front door outside handle assembly (for driver door) [electrical key antenna] at intervals of 250 ms. For the front door outside handle assembly (for driver door) [electrical key antenna] to detect when the key is brought close to the vehicle, a signal requesting a response from the key is transmitted within approximately 1 m (3.28 ft.) of the driver door at intervals of 250 ms. DTC B27A1 is stored by the certification ECU (smart key ECU assembly) when an open circuit is detected between the certification ECU (smart key ECU assembly) and front door outside handle assembly (for driver door) [electrical key antenna] (between terminals CLG1 and ANT1, or terminals CG1B and ANT2).

DTC CodeDTC Detection ConditionTrouble AreaDTC Output Confirmation Operation
B27A1An open circuit is detected in the circuit between the certification ECU (smart key ECU assembly) and front door outside handle assembly (for driver door) (CLG1 - ANT1, CG1B - ANT2) (This is detected by the malfunction detection circuit in the certification ECU (smart key ECU assembly)) (1 trip detection logic*).Harness or connector Front door outside handle assembly (for driver door) Certification ECU (smart key ECU assembly)Any time
  1. *: Only output while a malfunction is present.
Vehicle Condition when Malfunction DetectedFail-safe Operation when Malfunction Detected
Entry lock/unlock operation cannot be performed for driver door

VEHICLE CONDITION AND FAIL-SAFE OPERATION WHEN MALFUNCTION DETECTED

DTC CodeData List and Active Test
B27A1Key diagnostic mode can be used to perform troubleshooting

RELATED DATA LIST AND ACTIVE TEST

Scheme 194

Scheme 194: WIRING DIAGRAM

The certification ECU (smart key ECU assembly) generates a request signal and transmits the signal to the front door outside handle assembly (front passenger door) [electrical key antenna] at intervals of 250 ms. For the front door outside handle assembly (front passenger door) [electrical key antenna] to detect when the key is brought close to the vehicle, a signal requesting a response from the key is transmitted within approximately 1 m (3.28 ft.) of the front passenger door at intervals of 250 ms. DTC B27A2 is stored by the certification ECU (smart key ECU assembly) when an open circuit is detected between the certification ECU (smart key ECU assembly) and front door outside handle assembly (front passenger door) [electrical key antenna] (between terminals CLG2 and ANT1, or terminals CG2B and ANT2).

DTC CodeDTC Detection ConditionTrouble AreaDTC Output Confirmation Operation
B27A2An open circuit is detected in the circuit between the certification ECU (smart key ECU assembly) and front door outside handle assembly (front passenger door) (CLG2 - ANT1, CG2B - ANT2) (1 trip detection logic*).Harness or connector Front door outside handle assembly (front passenger door) Certification ECU (smart key ECU assembly)Any time
  1. *: Only output while a malfunction is present.
Vehicle Condition when Malfunction DetectedFail-safe Operation when Malfunction Detected
Entry lock/unlock operation cannot be performed for front passenger door

VEHICLE CONDITION AND FAIL-SAFE OPERATION WHEN MALFUNCTION DETECTED

DTC CodeData List and Active Test
B27A2Key diagnostic mode can be used to perform troubleshooting

RELATED DATA LIST AND ACTIVE TEST

Scheme 195

Scheme 195: WIRING DIAGRAM

The certification ECU (smart key ECU assembly) generates a request signal and transmits the signal to the No. 1 indoor electrical key antenna assembly (front floor). For the No. 1 indoor electrical key antenna assembly (front floor) to detect when the key is inside the vehicle, the signal from the certification ECU (smart key ECU assembly) requesting a response from the key is transmitted inside the vehicle. DTC B27A5 is stored by the certification ECU (smart key ECU assembly) when an open circuit is detected between the certification ECU (smart key ECU assembly) and No. 1 indoor electrical key antenna assembly (front floor) (between terminals CLG5 and CLG3, or terminals CG5B and CLGB).

DTC CodeDTC Detection ConditionTrouble AreaDTC Output Confirmation Operation
B27A5An open circuit is detected in the circuit between the certification ECU (smart key ECU assembly) and No. 1 indoor electrical key antenna assembly (front floor) (CLG5 - CLG3, CG5B - CLGB) (1 trip detection logic*).Harness or connector No. 1 indoor electrical key antenna assembly (front floor) Certification ECU (smart key ECU assembly)Any time
  1. *: Only output while a malfunction is present.
Vehicle Condition when Malfunction DetectedFail-safe Operation when Malfunction Detected
When key is in front seat area: Power source mode does not change when power switch pressed Key locked inside vehicle

VEHICLE CONDITION AND FAIL-SAFE OPERATION WHEN MALFUNCTION DETECTED

DTC CodeData List and Active Test
B27A5Key diagnostic mode can be used to perform troubleshooting

RELATED DATA LIST AND ACTIVE TEST

Scheme 196

Scheme 196: WIRING DIAGRAM

The certification ECU (smart key ECU assembly) generates a request signal and transmits the signal to the No. 2 indoor electrical key antenna assembly (rear floor). For the No. 2 indoor electrical key antenna assembly (rear floor) to detect when the key is inside the vehicle, the signal from the certification ECU (smart key ECU assembly) requesting a response from the key is transmitted inside the vehicle. DTC B27A6 is stored by the certification ECU (smart key ECU assembly) when an open circuit is detected between the certification ECU (smart key ECU assembly) and No. 2 indoor electrical key antenna assembly (rear floor) (between terminals CLG6 and CLG4, or terminals CG6B and CLGB).

DTC CodeDTC Detection ConditionTrouble AreaDTC Output Confirmation Operation
B27A6An open circuit is detected in the circuit between the certification ECU (smart key ECU assembly) and No. 2 indoor electrical key antenna assembly (rear floor) (CLG6 - CLG4, CG6B - CLGB) (1 trip detection logic*).Harness or connector No. 2 indoor electrical key antenna assembly (rear floor) Certification ECU (smart key ECU assembly)Any time
  1. *: Only output while a malfunction is present.
Vehicle Condition when Malfunction DetectedFail-safe Operation when Malfunction Detected
When key is in rear seat area: Power source mode does not change when power switch pressed Key locked inside vehicle

VEHICLE CONDITION AND FAIL-SAFE OPERATION WHEN MALFUNCTION DETECTED

DTC CodeData List and Active Test
B27A6Key diagnostic mode can be used to perform troubleshooting

RELATED DATA LIST AND ACTIVE TEST

Scheme 197

Scheme 197: WIRING DIAGRAM

The certification ECU (smart key ECU assembly) generates a request signal and transmits the signal to the No. 3 indoor electrical key antenna assembly (inside luggage). For the No. 3 indoor electrical key antenna assembly (inside luggage) to detect when the key is inside the luggage compartment, the signal from the certification ECU (smart key ECU assembly) requesting a response from the key is transmitted inside the luggage compartment. DTC B27A7 is stored by the certification ECU (smart key ECU assembly) when an open circuit is detected between the certification ECU (smart key ECU assembly) and No. 3 indoor electrical key antenna assembly (inside luggage) (between terminals CLG7 and CLG6, or terminals CG7B and CLGB).

DTC CodeDTC Detection ConditionTrouble AreaDTC Output Confirmation Operation
B27A7An open circuit is detected in the circuit between the certification ECU (smart key ECU assembly) and No. 3 indoor electrical key antenna assembly (inside luggage) (CLG7 - CLG6, CG7B - CLGB) (1 trip detection logic*).Harness or connector No. 3 indoor electrical key antenna assembly (inside luggage) Certification ECU (smart key ECU assembly)Any time
  1. *: Only output while a malfunction is present.
Vehicle Condition when Malfunction DetectedFail-safe Operation when Malfunction Detected
When key is in luggage compartment: Power source mode does not change when power switch is pressed Key becomes locked inside vehicle

VEHICLE CONDITION AND FAIL-SAFE OPERATION WHEN MALFUNCTION DETECTED

DTC CodeData List and Active Test
B27A7Key diagnostic mode can be used to perform troubleshooting

RELATED DATA LIST AND ACTIVE TEST

Scheme 198

Scheme 198: WIRING DIAGRAM

The certification ECU (smart key ECU assembly) generates a request signal and transmits the signal to the electrical key antenna (outside luggage). For the electrical key antenna (outside luggage) to detect when the key is brought close to the vehicle, the received request signal is transmitted within approximately 1.0 m (3.28 ft.) of the back door. DTC B27A8 is stored by the certification ECU (smart key ECU assembly) when an open circuit is detected between the certification ECU (smart key ECU assembly) and electrical key antenna (outside luggage) (between terminals CLG8 and CLG5, or terminals CG8B and CLGB).

DTC CodeDTC Detection ConditionTrouble AreaDTC Output Confirmation Operation
B27A8An open circuit is detected in the circuit between the certification ECU (smart key ECU assembly) and electrical key antenna (outside luggage) (CLG8 - CLG5, CG8B - CLGB) (1 trip detection logic*).Harness or connector Electrical key antenna (outside luggage) Certification ECU (smart key ECU assembly)Any time
  1. *: Only output while a malfunction is present.
Vehicle Condition when Malfunction DetectedFail-safe Operation when Malfunction Detected
Entry lock/unlock operation cannot be performed for back door

VEHICLE CONDITION AND FAIL-SAFE OPERATION WHEN MALFUNCTION DETECTED

DTC CodeData List and Active Test
B27A8Key diagnostic mode can be used to perform troubleshooting

RELATED DATA LIST AND ACTIVE TEST

Scheme 199

Scheme 199: WIRING DIAGRAM

The smart access system with push-button start uses the wireless door lock buzzer assembly to perform various vehicle exterior warnings. When the conditions for each warning are met, the certification ECU (smart key ECU assembly) sends a buzzer request signal to the main body ECU (multiplex network body ECU) via CAN communication. The wireless door lock assembly sounds the buzzer according to the signal from the main body ECU (multiplex network body ECU).

When the entry operation and wireless operation of the door lock functions do not operate, a malfunction or wave interference may be occurring in either of the following: 1) the signal communication line between the door control receiver and certification ECU (smart key ECU assembly) (the line used for entry and wireless operations); or 2) the electrical key transmitter. If the entry lock and wireless lock operations cannot be performed, there may be key malfunctions, wave interference or problems in the communication which is used for the entry and wireless function between the door control receiver and certification ECU (smart key ECU assembly).

Scheme 200

Scheme 200: WIRING DIAGRAM

When the wireless operation can be used to lock and unlock the doors, communication between the door control receiver and certification ECU (smart key ECU assembly) is normal. If the entry lock and unlock functions do not operate, the entry cancel function may be set through the customize function, there may be communication problems between the key and vehicle, or there may be electric wave interference.

If the entry unlock function does not operate for the driver door only, but the entry lock function operates, the request code is being transmitted properly from the driver door. In this case, there may be a problem related to the touch sensor (connection between the certification ECU (smart key ECU assembly) and front door outside handle assembly (for driver door) [unlock sensor]).

Scheme 201

Scheme 201: WIRING DIAGRAM

If the entry unlock function does not operate for the front passenger door only, but the entry lock function operates, the request code is being transmitted properly from the front passenger door. In this case, there may be a problem related to the touch sensor (connection between the certification ECU (smart key ECU assembly) and front door outside handle assembly (for front passenger door) [unlock sensor]).

Scheme 202

Scheme 202: WIRING DIAGRAM

If the entry lock and unlock functions do not operate for the driver door only, the request code may not be being transmitted from the driver door or the front door outside handle assembly (for driver door) (touch sensor) may be malfunctioning. If the entry functions for other doors operate properly, communication between the key and door control receiver is normal. In this case, there may be a problem with request code transmission (communication between the certification ECU (smart key ECU assembly) and front door outside handle assembly (for driver door) [driver door electrical key antenna]), or there may be wave interference.

Scheme 203

Scheme 203: WIRING DIAGRAM

If the entry lock and unlock functions do not operate for the front passenger door only, the request code may not be being transmitted from the front passenger door or the front door outside handle assembly (for front passenger door) (touch sensor) may be malfunctioning. If the entry functions for other doors operate properly, communication between the key and door control receiver is normal. In this case, there may be a problem with request code transmission (communication between the certification ECU (smart key ECU assembly) and front door outside handle assembly (for front passenger door) [front passenger door electrical key antenna]), or there may be wave interference.

Scheme 204

Scheme 204: WIRING DIAGRAM

If the entry lock function does not operate for the driver door only, but the entry unlock function operates, the request code is being transmitted properly from the driver door. In this case, there may be a problem related to the front door outside handle assembly (for driver door) (lock sensor) (connection between the certification ECU (smart key ECU assembly) and front door outside handle assembly (for driver door) [lock sensor]).

Scheme 205

Scheme 205: WIRING DIAGRAM

If the entry lock function does not operate for the front passenger door only, but the entry unlock function operates, the request code is being transmitted properly from the front passenger door. In this case, there may be a problem related to the front door outside handle assembly (for front passenger door) (lock sensor) (connection between the certification ECU (smart key ECU assembly) and front door outside handle assembly (for front passenger door) [lock sensor]).

Scheme 206

Scheme 206: WIRING DIAGRAM

If code verification cannot be performed in the vehicle interior, there may be problems with the communication between the vehicle (indoor electrical key antenna assembly [front floor], [rear floor] or [inside luggage]) and key, or the certification ECU (smart key ECU assembly) may be malfunctioning. When the key is brought into the vehicle, verification of the key ID code transmitted from the key and the key ID code stored in the certification ECU (smart key ECU assembly) is performed. If verification cannot be performed or the codes do not match, the power switch cannot be turned on (IG) and the hybrid control system cannot be started.

When a door is unlocked and the key is brought into the vehicle, the certification ECU (smart key ECU assembly) activates the indoor electrical key antenna assembly which transmits electric waves to detect the key. If the key recognizes that it is in the detection area, it responds with the key ID code. This information is received by the indoor electrical key antenna and then sent to the certification ECU (smart key ECU assembly).

Scheme 207

Scheme 207: WIRING DIAGRAM

The smart access system with push-button start (for Entry Function) uses the buzzer in the combination meter assembly (meter ECU) to perform various vehicle interior warnings. When the conditions of each warning are met, the certification ECU (smart key ECU assembly) sends a buzzer activation request signal to the combination meter assembly (meter ECU) via CAN communication and the buzzer sounds.

If the entry unlock function does not operate for the back door only, but the entry lock function operates, the request code is being transmitted properly from the back door. In this case, there may be a problem related to the unlock switch (connection between the back door opener switch assembly and certification ECU (smart key ECU assembly)).

Scheme 208

Scheme 208: WIRING DIAGRAM

If the entry lock and unlock functions do not operate for the back door only, the request code may not be being transmitted from the back door. If the entry functions for other doors operate properly, communication between the key and door control receiver is normal. In this case, there may be a problem with request code transmission (communication between the certification ECU (smart key ECU assembly) and electrical key antenna [outside luggage]), or there may be electric wave interference.

Scheme 209

Scheme 209: WIRING DIAGRAM

If the entry lock function does not operate for the back door only, but the entry unlock function operates, the request code is being transmitted properly from the back door. In this case, there may be a problem related to the lock switch (connection between the back door opener switch assembly and certification ECU (smart key ECU assembly)).

Scheme 210

Scheme 210: WIRING DIAGRAM