Diagnosis System [08/2013 - ]

WARNING: This page is about a different car, the 2018 Toyota Corolla, 2017 Toyota Corolla, 2016 Toyota Corolla, 2015 Toyota Corolla, and 2014 Toyota Corolla. However, it is still accessible from the selected car via links, so may be relevant.

DESCRIPTION
1. The certification ECU (smart key ECU assembly) and ECM control the vehicle immobilizer system functions. Immobilizer 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 immobilizer 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
1. Check the DLC3.
  Refer to GENERAL INFORMATION [08/2013 - ]
INSPECT BATTERY VOLTAGE
1. 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 B2790 B2799 B279A	Ignition Switch #Codes Immobilizer when IG=ON Immobilizer 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 (immobilizer code ECU)	Open or short circuit inside ECU	B2790 B2799 B279A	Immobilizer when IG=ON Immobilizer 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 immobilizer system	B279C	Engine Start Condition EFI Code Receive
Power source mode cannot be changed*1	Engine switch	Open or short circuit inside switch	B278A	Ignition Switch 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	Ignition Switch Immobilizer when IG=ON Immobilizer
Steering lock lock/unlock not possible*2	Steering lock ECU (steering lock actuator 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).
Refer to PROBLEM SYMPTOMS TABLE [08/2013 - ]
*2: Refer to Problem Symptoms Table for Steering Lock System.
Refer to PROBLEM SYMPTOMS TABLE [08/2013 - ]