Toyota CH-R Service Manual: Diagnosis System

Toyota CH-R Service Manual / Theft Deterrent / Keyless Entry / Immobiliser System(w/ Smart Key System) / Diagnosis System

DIAGNOSIS SYSTEM

DESCRIPTION

(a) The certification ECU (smart key ECU assembly) and ECM control the vehicle immobiliser system functions. Immobiliser system data and Diagnostic Trouble Codes (DTCs) can be read through the vehicle Data Link Connector 3 (DLC3).

In some cases, a malfunction may be occurring in the immobiliser system even though the security indicator light is not illuminated.

When the system seems to be malfunctioning, use the Techstream to check for malfunctions and perform repairs.

CHECK DLC3

(a) Check the DLC3.

Click here

INSPECT BATTERY VOLTAGE

(a) Measure the battery voltage.

Standard Voltage:

11 to 14 V

If the voltage is below 11 V, recharge or replace the battery.

START FUNCTION PROBLEM SYMPTOMS

Symptom	Suspected Area	Component Malfunction	Possible Output DTCs	Related Data List Item
Engine cannot be started*1	Certification ECU (smart key ECU assembly)	Open or short circuit inside ECU	B278A B2799 B279A	#Codes Immobilizer when IG=ON Immobiliser Master Key Sub Key BCC Malfunction Abnormal Status Different Encrypt Code Different Serial Number Frame Error Response Wireless Starter Com ID Wireless C Code Engine Start Condition ID-BOX Sleep Condition ID-BOX Start Condition Engine Start Request 3bit Code Request S Code Check L Code Check Unlock Request Receive Lock Request Receive S Code Check (Past) L Code Check (Past) EFI Code Receive EFI Communication
Engine cannot be started*1	ID code box (immobiliser code ECU)	Open or short circuit inside ECU	B2790 B2799 B279A	Immobilizer when IG=ON Immobiliser Master Key Sub Key BCC Malfunction Abnormal Status Different Encrypt Code Different Serial Number Frame Error Response ID-BOX Sleep Condition ID-BOX Start Condition Engine Start Request 3bit Code Request S Code Check L Code Check S Code Check (Past) L Code Check (Past) EFI Code Receive EFI Communication
	ECM	Open or short circuit inside ECU	B2799 B279A B279C	EFI Code Receive
	SFI system	ECM incompatible with installed immobiliser system	B279C	Engine Start Condition EFI Code Receive
Power source mode cannot be changed*1	Engine switch	Open or short circuit inside switch	B278A	Unlock Request Receive Lock Request Receive
Power source mode cannot be changed*1	Certification ECU (smart key ECU assembly)	Open or short circuit inside ECU	B2271 B2274	Immobilizer when IG=ON Immobiliser
Steering lock lock/unlock not possible*2	Steering lock ECU (steering lock actuator or upper bracket assembly)	Open or short circuit inside ECU Actuator stuck	B2781 B2782 B2788	Unlock Request Receive Lock Request Receive

*1: Refer to Problem Symptoms Table for Smart Key System (for Start Function).
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*2: Refer to Problem Symptoms Table for Steering Lock System.
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Terminals Of Ecu

TERMINALS OF ECU CHECK ENGINE SWITCH (a) Measure the voltage and resistance according to the value(s) in the table below. Terminal No. (Symbol) Input/Output Wir ...

Dtc Check / Clear

DTC CHECK / CLEAR NOTICE: When using the Techstream with the engine switch off, connect the Techstream to the DLC3 and turn a courtesy light switch on and off at intervals of 1.5 seconds or less ...

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Toyota CH-R Service Manual: Diagnosis System

Terminals Of Ecu

Dtc Check / Clear

Other materials:

Toyota C-HR (AX20) 2023-2025 Owner's Manual

Toyota CH-R Owners Manual

Toyota CH-R Service Manual