Toyota Yaris: Smart Key System (for Start Function) / Problem Symptoms Table

Toyota Yaris XP210 (2020-2025) Reapir and Service Manual / Vehicle Interior / Theft Deterrent / Keyless Entry / Smart Key System (for Start Function) / Problem Symptoms Table

PROBLEM SYMPTOMS TABLE

HINT:

Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.
Inspect the fuses and relays related to the system before inspecting the suspected areas below.
If the problem occurs in certain locations or times of day, the possibility of wave interference is high.
If a malfunction occurred after optional components were installed by the dealer, check if there is wave interference from the components.

Smart Key System (for Start Function)

Symptom	Suspected Area	Link
Power source mode does not change to on (IG) or on (ACC)	Smart key system (for Entry Function)
	Affected by wave interference
	Transmitter battery
	Electrical key transmitter sub-assembly
	No. 1 indoor electrical key antenna assembly (front floor)
	No. 2 indoor electrical key antenna assembly (rear floor)
	Engine switch
	Wire harness or connector
	Power distribution box assembly
	Certification ECU (Smart key ECU assembly)
Power source mode does not change to on (IG)	Wire harness or connector
	Relay - IGR NO. 1 relay - IGR NO. 2 relay - IGP relay
	Power distribution box assembly
	Certification ECU (Smart key ECU assembly)
Power source mode does not change to on (ACC)	Wire harness or connector
	Relay - ACC relay
	Power distribution box assembly
	Certification ECU (Smart key ECU assembly)
Engine does not start	Transmitter battery
	Affected by wave interference
	SFI system
	Steering lock function
	Immobiliser function
	Wire harness or connector
	ST NO. 1 fuse
	ST relay
	Clutch switch assembly
	Electrical key transmitter sub-assembly
	Stop light switch assembly
	Certification ECU (Smart key ECU assembly)
New key cannot be registered	LIN communication system
	Meter / gauge system
	Reregistration
	Electrical key transmitter sub-assembly
	Steering lock ECU (Steering lock actuator or upper bracket assembly)
	ID code box (Immobiliser code ECU)
	Certification ECU (Smart key ECU assembly)
Additional key cannot be registered	Steering lock function
	Reregistration
	Electrical key transmitter sub-assembly
	ID code box (Immobiliser code ECU)
	Certification ECU (Smart key ECU assembly)
New key registration warning message is not displayed	Lighting system (int)
	Meter / gauge system
	Certification ECU (Smart key ECU assembly)
Unable to unlock steering wheel (Engine cannot start)	Wire harness or connector
	Steering lock ECU (Steering lock actuator or upper bracket assembly)
	ID code box (Immobiliser code ECU)
	Certification ECU (Smart key ECU assembly)
Steering lock does not lock	Lighting system (int)
	Wire harness or connector
	Steering lock ECU (Steering lock actuator or upper bracket assembly)
	ID code box (Immobiliser code ECU)
	Certification ECU (Smart key ECU assembly)
Security indicator light does not blink	Wire harness or connector
	Security indicator light (Combination meter assembly)
	Certification ECU (Smart key ECU assembly)
Immobiliser system does not operate properly	Communication ID registration was defective
	Wire harness or connector
	ID code box (Immobiliser code ECU)
	ECM
System malfunction message is displayed on the multi-information display	Smart key system (for Entry Function)
	Smart key system (for Start Function)
	Steering lock ECU (Steering lock actuator or upper bracket assembly)
	Certification ECU (Smart key ECU assembly)
	Clutch start switch assembly
	Electronically controlled brake system

Customize Parameters

CUSTOMIZE PARAMETERS CUSTOMIZE SMART KEY SYSTEM (for Start Function) NOTICE: When the customer requests a change in a function, first make sure that the function can be customized...

Terminals Of Ecu

TERMINALS OF ECU CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (a) Disconnect the H45 and H46 certification ECU (smart key ECU assembly) connectors...

Other information:

Toyota Yaris XP210 (2020-2025) Reapir and Service Manual: IG Signal Circuit

DESCRIPTION This circuit detects the ignition switch ON or off condition, and sends it to the main body ECU (multiplex network body ECU). WIRING DIAGRAM CAUTION / NOTICE / HINT NOTICE: Inspect the fuses for circuits related to this system before performing the following procedure...

Toyota Yaris XP210 (2020-2025) Reapir and Service Manual: Problem Symptoms Table

PROBLEM SYMPTOMS TABLE NOTICE: Before replacing the main body ECU (multiplex network body ECU) or certification ECU (smart key ECU assembly), refer to Registration. Click here HINT: Use the table below to help determine the cause of problem symptoms...