T-SB-0011-25

January 23, 2025

ECU Security Key Writing
Service
Category

Power Source/Network
Market USA and

Section

Mexico

Networking

Applicability
YEAR(S)

MODEL(S)

2025

4Runner, 4Runner HV,
Camry HV, Crown Signia,
Prius PHV, RAV4 PHV

2022 - 2025

86, Corolla Cross, Tundra
HV

2024 - 2025

Grand Highlander, Grand
Highlander HV, Highlander,
Highlander HV, Land
Cruiser, Tacoma, Tacoma
HV

2021 - 2025

Mirai, Sienna HV, Tundra,
Venza HV

2023 - 2024

Prius Prime

2021 - 2024

RAV4 Prime

2023 - 2025

bZ4X, Corolla, Corolla Cross
HV, Corolla HV, Crown, GR
Corolla, Prius, Sequoia HV,
Yaris

ADDITIONAL INFORMATION

SUPERSESSION NOTICE
The information contained in this bulletin supersedes Service Bulletin No. T-SB-0111-20.
 Applicability has been updated to include 2023 – 2025 model year Corolla Hybrid,
2024 – 2025 model year Land Cruiser, Tacoma, and Tacoma Hybrid, and 2025 model year
4Runner, 4Runner Hybrid, 86, bZ4X, Camry Hybrid, Corolla, Corolla Cross,
Corolla Cross Hybrid, Corolla Hybrid, Crown, Crown Signia, GR Corolla, Grand Highlander,
Grand Highlander Hybrid, Highlander, Highlander Hybrid, Mirai, Prius, Prius PHV, RAV4 PHV,
Sequoia Hybrid, Sienna Hybrid, Tundra, Tundra Hybrid, Venza Hybrid, and Yaris vehicles.
Service Bulletin No. T-SB-0111-20 is obsolete and any printed versions should be discarded.

© 2025 Toyota Motor Sales, USA

Page 1 of 11

T-SB-0011-25

January 23, 2025

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ECU Security Key Writing
Introduction

When certain vehicle ECUs are replaced, the ECU Security Key must be written in order for that
ECU to communicate on the vehicle network. The GTS+ Software Health Check Results screen
has been enhanced to help identify if a replacement ECU requires an ECU Security Key. Follow the
procedures in this bulletin to write the ECU Security Key to the replacement ECU.
Figure 1.

Warranty Information
For USA and Mexico Markets
OP CODE

DESCRIPTION

TIME

OFP

T1

T2

N/A

Not Applicable to Warranty

–

–

–

–

© 2025 Toyota Motor Sales, USA

T-SB-0011-25

January 23, 2025

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ECU Security Key Writing
Required Tools & Equipment
REQUIRED EQUIPMENT

SUPPLIER

Techstream ADVi*

PART NUMBER

QTY

TSADVUNIT

Techstream 2.0

TS2UNIT
ADE

1

Techstream Lite

TSLITEPDLR01

Techstream Lite (Green Cable)

TSLP2DLR01

*Essential SST.

NOTE
 Only ONE of the Techstream units listed above is required.
 Software version 2024.04.004.02 or later is required.
 Additional Techstream units may be ordered by calling Approved Dealer Equipment (ADE)
at 1-800-368-6787 (USA) or 01-55-50103041 (Mexico) or by visiting TIS – Diagnostics –
Tools & Equipment – Techstream Order Portal.

SPECIAL SERVICE TOOLS (SST)

PART NUMBER

QTY

Battery Diagnostic Tool*

DCA-8000P T

1

*Essential SST.

NOTE
Additional SSTs may be ordered by calling 1-800-368-6787 (USA) or 01-800-504-5330 (Mexico) or by
visiting Home – Service Resources – Toyota Special Service Tools (SSTs).

Procedures





Confirm ECU Security Key Writing Requirement ..................................................................... 4


Health Check...................................................................................................................... 4



ECU Security Key Button ................................................................................................... 5

ECU Security Key Writing Process .......................................................................................... 6

© 2025 Toyota Motor Sales, USA

T-SB-0011-25

January 23, 2025

Page 4 of 11

ECU Security Key Writing
Confirm ECU Security Key Writing Requirement

After ECU replacement, it is important to confirm if ECU Security Key writing is necessary. There
are two methods available to confirm if the ECU Security Key writing function is required within
the GTS+ software: performing a Health Check and using the ECU Security Key button.
Health Check

Performing a Health Check will confirm if ECU Security Key writing is needed. The GTS+ Health
Check Results screen has been enhanced to include an ECU Security Key indicator. The ECU
Security Key indicator will display “Necessary” when an ECU Security Key needs to be written
and “-” when ECU Security Key writing is NOT required.
Figure 2.

© 2025 Toyota Motor Sales, USA

T-SB-0011-25

January 23, 2025

Page 5 of 11

ECU Security Key Writing
Confirm ECU Security Key Writing Requirement (continued)
ECU Security Key Button

Selecting the ECU Security Key button is another method to confirm if ECU Security Key writing is
required. From the Main Menu screen, select the ECU Security Key button.
Figure 3.

NOTE
Selecting this option can allow ECU Security Key writing even if it is not required. If the ECU Security Key
does NOT need to be written, a message will appear stating “ECU Security Key is already written.”
Figure 4.

© 2025 Toyota Motor Sales, USA

T-SB-0011-25

January 23, 2025

Page 6 of 11

ECU Security Key Writing
ECU Security Key Writing Process
NOTE
The process outlined in this section will use the Health Check Result screen to confirm if ECU Security
Key writing is required.

1. Connect GTS+ to the vehicle and press the arrow button to go to the next step.
NOTE
In some instances, automatic vehicle detection may not be available due to specific ECU
replacement. If the vehicle information does NOT automatically populate, manually select the
appropriate vehicle information.
Figure 5.

© 2025 Toyota Motor Sales, USA

T-SB-0011-25

January 23, 2025

Page 7 of 11

ECU Security Key Writing
ECU Security Key Writing Process (continued)

2. Perform a Health Check.
If the ECU Security Key indicator in the upper lefthand corner of the Health Check screen
displays “Necessary,” navigate to the Main Menu and select the ECU Security Key button as
shown below.
Figure 6.

Figure 7.

© 2025 Toyota Motor Sales, USA

T-SB-0011-25

January 23, 2025

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ECU Security Key Writing
ECU Security Key Writing Process (continued)

3. Select Next to begin ECU Security Key writing.
Figure 8.

4. GTS+ will read the vehicle information. Select Next to send the information to the server.
Figure 9.

© 2025 Toyota Motor Sales, USA

T-SB-0011-25

January 23, 2025

ECU Security Key Writing
ECU Security Key Writing Process (continued)

5. Select OK to login.
Figure 10.

6. Enter your TIS password and select LOG IN.
Figure 11.

© 2025 Toyota Motor Sales, USA

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T-SB-0011-25

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ECU Security Key Writing
ECU Security Key Writing Process (continued)

7. Cycle the ignition to IG-OFF, and then IG-ON. Select Next.
Figure 12.

8. Select OK.
Figure 13.

© 2025 Toyota Motor Sales, USA

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T-SB-0011-25

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ECU Security Key Writing
ECU Security Key Writing Process (continued)

9. Confirm the ECU Security Key has been properly written by performing a Health Check and
confirming the ECU Security Key indicator shows “-”, and then clear ALL DTCs.
Figure 14.

NOTE
The ECU Security Key indicator will show “Necessary” if the Security Key was NOT written properly.
If NOT written properly, return to step 2.

© 2025 Toyota Motor Sales, USA