Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Repair Instruction: Initialization
- PROCEDURES NECESSARY WHEN ECU OR OTHER PARTS ARE REPLACED ECU OR OTHER PARTS REPLACEMENT PROCEDURES
Replacement Part Necessary Procedure Effect / Inoperative Function when Necessary Procedures are not Performed Note ECM Vehicle Identification Number (VIN) registration MIL comes on Using the Techstream. ECU communication ID registration Engine start - Reset memory - Large shift shock
- The deterioration of fuel efficiency
Using the Techstream. Tire pressure warning ECU - Register transmitter IDs
- Initialize tire pressure warning system
- When DTC detection conditions of "transmitter ID not received" DTC are met, TPWS indicator blinks for 1 minute, and then illuminates.
- Tire pressure monitoring function
- Tire pressure warning valve and transmitter - Register transmitter IDs
- Initialize tire pressure warning system
- When DTC detection conditions of "transmitter ID not received" DTC are met, TPWS indicator blinks for 1 minute, and then illuminates.
- Tire pressure monitoring function of replaced wheel
Even if only one wheel is replaced, IDs for all 4 wheels must be registered. Brake actuator assembly (Skid control ECU) Perform yaw rate and acceleration sensor zero point calibration - VSC OFF indicator light blinks
- VSC disabled or malfunctioning
Perform yaw rate and acceleration sensor zero point calibration with the ignition switch on (engine stopped). - Yaw rate and acceleration sensor
- Front wheel alignment adjustment
- Clear zero point calibration data
- Perform yaw rate and acceleration sensor zero point calibration
- VSC OFF indicator light blinks
- VSC disabled or malfunctioning
Perform yaw rate and acceleration sensor zero point calibration with the ignition switch on (engine stopped). - Power steering ECU
- Power steering link assembly
Perform rotation angle sensor initialization and torque sensor zero point calibration - P/S warning light comes on
- EPS control
DTC (C1515/C1525) will be stored when the power steering ECU is replaced. Transponder key ECU - Key code registration
- ECU communication ID registration
Engine start - Key Key code registration Engine start - - Door control transmitter
- Door control receiver
Refer to the appropriate code registration procedures. Wireless door lock control system - Front seat cushion assembly (w/ occupant classification ECU, occupant classification sensor) - Perform zero point calibration
- Sensitivity check
- Occupant classification system
- Passenger airbag ON/OFF indicator
- Airbag system (Front passenger side)
- Seat belt warning system (Front passenger side)
- - Sliding roof drive gear sub-assembly (Sliding roof ECU)
- Sliding roof housing
Perform sliding roof drive gear reset - Automatic open/close function of roof glass
- Jam protection function
- Operation function after ignition switch off
Necessary when removed and installed (not necessary when the sliding roof drive gear (sliding roof ECU) is removed and installed together with the sliding roof housing). (1) for U140F, U250E, U341E Automatic Transaxle - VEHICLE IDENTIFICATION NUMBER (VIN) REGISTRATION NOTE: The Vehicle Identification Number (VIN) must be input into a replacement ECM.
HINT:
The VIN is a 17-digit alphanumeric vehicle identification number. The Techstream is required to register the VIN.
- Description
HINT:
This registration section consists of two parts: Read VIN and Write VIN.
- Read VIN: This process allows the VIN stored in the ECM to be read in order to confirm that the two VINs, provided with the vehicle and stored in the vehicle's ECM, are the same.
- Write VIN: This process allows the VIN to be input into the ECM. If the ECM is changed, or the ECM VIN and vehicle VIN do not match, the VIN can be registered, or overwritten in the ECM by following procedure.
- Read VIN
- Confirm the vehicle VIN.
- Connect the Techstream to the DLC3.
- Turn the ignition switch to ON.
- Turn the Techstream on.
- Enter the following menus: Powertrain / Engine and ECT / Utility / VIN / VIN Read.
- Write VIN
- Confirm the vehicle VIN.
- Connect the Techstream to the DLC3.
- Turn the ignition switch to ON.
- Turn the Techstream on.
- Enter the following menus: Powertrain / Engine and ECT / Utility / VIN / VIN Write.
- Description
- DESCRIPTION OF CODE REGISTRATION (Engine Immobilizer System)
HINT:
The key has 2 codes: the key code (immobilizer code) and the wireless code. Both of these codes need to be registered. Refer to appropriate code registration procedures.
- When adding master keys or sub keys (Additional registration):
- Register the key code (immobilizer code) in the transponder key ECU.
TRANSPONDER KEY ECU KEY CODE REGISTRATION PROCEDURETarget ECU Refer to Transponder key ECU Procedure "B" - When replacing the transponder key ECU (New registration):
- Register the key code (immobilizer code) in the transponder key ECU.TRANSPONDER KEY ECU KEY CODE REGISTRATION PROCEDURE
Target ECU Refer to Transponder key ECU Procedure "A" - Register the ECU communication ID between the new transponder key ECU and the ECM.
ECM KEY CODE REGISTRATION PROCEDURETarget ECU Refer to ECM Procedure "D" - Register the key code (immobilizer code) in the transponder key ECU.
- When replacing the ECM:
- Register the ECU communication ID between the transponder key ECU and the new ECM.
TRANSPONDER KEY ECU KEY CODE REGISTRATION PROCEDURETarget ECU Refer to Transponder key ECU Procedure "E" - When replacing the transponder key ECU and the ECM:
- Register the key codes (immobilizer codes) in the new transponder key ECU.TRANSPONDER KEY ECU KEY CODE REGISTRATION PROCEDURE
Target ECU Refer to Transponder key ECU Procedure "A" - Register the ECU communication ID between the new transponder key ECU and the new ECM.
TRANSPONDER KEY ECU KEY CODE REGISTRATION PROCEDURETarget ECU Refer to Transponder key ECU Procedure "E" - Register the key codes (immobilizer codes) in the new transponder key ECU.
- When erasing the key code(s):
- Erase the key code(s) of lost key(s).
TRANSPONDER KEY ECU KEY CODE REGISTRATION PROCEDURETarget ECU Refer to Transponder key ECU Procedure "C"
- When adding master keys or sub keys (Additional registration):
- KEY REGISTRATION (Engine Immobilizer System)
- New key code registration (Procedure "A"):NOTE: This is the condition that no key codes are registered in the transponder key ECU.
HINT:
- In this mode, a maximum of 2 master key codes can be registered.
- New key codes must be registered with the battery connected. The ignition switch can be either on or off.
- When a new transponder key ECU is installed, key codes must be registered in the transponder key ECU.
Automatic Key Code Registration (New Registration)
AUTOMATIC KEY CODE REGISTRATION PROCEDUREProcedure Security Indicator Light Condition 1. Start Blinking
HINT:
Until first key is inserted2. Insert the master key into the ignition key cylinder. ON 3. Techstream operation
Select the following menu items: Body Electrical / Immobilizer / Utility / Key Registration
HINT:
After completing the above operation, proceed to the next step in accordance with the prompts on the Techstream screen.OFF for 1 second and then ON 4. Remove the key and then push the Next button on the Techstream. ON 5. Insert the master key to be registered and then push the Next button on the Techstream. OFF for 1 second and then ON 6. Remove the key. Blinking 7. End (Procedure "E") HINT:
- A brief outline of key code registration procedure is shown above. For detailed information, refer to the Techstream screen.
- When the engine immobilizer system is operating normally and the key is pulled out, the security indicator light blinks continuously.
- If the new key code registration fails, code 2-1 will be output through the security indicator light. Trying to re-register an already registered key will cause code 2-2 to be output when the key is inserted. If the number of registered key codes exceeds the maximum limit, code 2-3 will be output through the security indicator light. The output details are shown as follows.
- Finish the automatic key code of registration mode. The automatic key code of registration mode can be forced to end when at least 1 key code (immobilizer code) for the master key has been registered.
HINT:
- without the Techstream:
- with the Techstream:
Turn the ignition switch ON and off 5 times within 10 seconds using the master key that has already been registered.
Follow the instruction on the Techstream screen to end new key code of registration mode.
- New key code registration (Procedure "A"):
- REGISTRATION OF ADDITIONAL KEY (Engine Immobilizer System)
- Additional registration (Procedure "B"):
HINT:
- A maximum of 5 key codes and 3 sub-key codes can be registered.
- Registration mode will end if any step is not completed within the specified time.
- When the ignition cylinder or the key cylinder set is replaced, remove the transmitter module from the original master key. Then install this transmitter module to a new key and use the new key as the master key. If necessary, use this master key to register other keys.
NOTE: When the ignition key cylinder has been replaced, locking and unlocking doors are possible with the new master key's transmitter module (removed from the original master key). However, the new master key will not be able to lock and unlock doors through the door key cylinder. Keep the original master key. If the battery in the new master key's transmitter module fails, the original master key can be used to lock and unlock doors through the door key cylinder.Additional Registration
ADDITIONAL KEY REGISTRATION PROCEDUREProcedure Time to Complete Operation Security Indicator Light Condition 1. Start - Blinking
HINT:
Until first key is inserted2. Insert the already registered master key into the ignition key cylinder and turn the ignition switch to ON. - OFF 3. Techstream operation
Select the following menu items: Body Electrical / Immobilizer; Utility / Key Registration
HINT:
After completing the above operation, proceed to the next step in accordance with the prompts on the Techstream screen.Within 120 sec. ON 4. Remove the master key. Within 20 sec.
HINT:
After the Techstream instructionON 5. Insert the key to be registered in the ignition key cylinder. Within 10 sec. Blinking 6. Wait for 60 sec. after the key is registered.
HINT:
The security indicator light goes off.- OFF 7. Remove the key. - Blinking 8. End HINT:
- A brief outline of key code registration procedure is shown above. For detailed information, refer to the Techstream screen.
- When the engine immobilizer system is operating normally and the key is pulled out, the security indicator light blinks continuously.
- If the key code registration has failed in automatic key code registration mode, code 2-1 will be output through the security indicator light. Trying to re-register an already registered key will cause code 2-2 to be output when the key is inserted. If the number of registered key codes exceeds the maximum limit, code 2-3 will be output through the security indicator light. The details are shown in procedure "A".
- Additional registration (Procedure "B"):
- ERASURE OF KEY CODE (Engine Immobilizer System)
- Erase key codes (Procedure "C"):
HINT:
- Performing this procedure will erase all key codes except for the master key, which is used for erasing the key codes. In order to use a key whose code has been erased, a new key code must be registered.
- This procedure will be canceled if each step is not completed within the specified time.
Erasing Key Code
ERASING KEY CODE PROCEDUREProcedure Time to Complete Operation Security Indicator Light Condition 1. Start - Blinking
HINT:
Until first key is inserted2. Insert the already registered master key in the ignition key cylinder and turn the ignition switch to ON. - OFF 3. Techstream operation
Select the following menu items: Body Electrical / Immobilizer / Utility / Transponder Code Erasure
HINT:
After completing the above operation, proceed to the next step in accordance with the prompts on the Techstream screen.Within 120 sec. ON for 1 second and then OFF 4. Remove the master key. Within 10 sec.
HINT:
After the Techstream instructionBlinking 5. End HINT:
- A brief outline of key code registration procedures is shown above. For detailed information, refer to the Techstream screen.
- When the engine immobilizer system is operating normally and the key is pulled out, the security indicator light blinks continuously.
- Erase key codes (Procedure "C"):
- ECU COMMUNICATION ID REGISTRATION (Engine Immobilizer System)
- ECU communication ID registration (Procedure "D"):NOTE:
- When the transponder key ECU is replaced, the ECU communication ID of the ECM must be registered into the transponder key ECU to match their ECU communication IDs.
- The engine cannot be started unless the ECU communication IDs match.
- Do not turn the ignition switch from ON to off 20 times or more before setting the ECU communication ID. Turning the ignition switch from ON to off 20 times or more will result in the engine not starting unless the transponder key ECU is replaced with a new one.
- After the registration, turning the ignition switch to the START position may not start the engine on the first try. If so, turn the ignition switch to the START position again.
- After the engine is started, erase DTC B2799 (code for ECM's immobilizer communication error) by either of the following:
- Using the Techstream.
- Disconnecting the battery for 30 seconds.
- Using SST, connect terminals TC and CG of the DLC3.
SST 09843-18040
- Turn the ignition switch to ON and leave the vehicle as is for 30 minutes.
HINT:
Do not start the engine.
- Check that the engine can be started.
- ECU communication ID registration (Procedure "E"):NOTE: The ECU communication ID should be registered when the ECM and transponder key ECU are replaced or when the ECM only is replaced in order to match the ECU communication ID.ECU COMMUNICATION ID REGISTRATION PROCEDURE
Procedure Security Indicator Light Condition 1. Start OFF 2. Insert an already registered key into the ignition key cylinder. 3. Start engine 4. Check that the engine starts and stays on for more than 3 seconds. 5. End
- ECU communication ID registration (Procedure "D"):
- RESET MEMORY (U140F Automatic Transaxle System) NOTE:
- Perform RESET MEMORY (AT initialization) when replacing the automatic transaxle assembly, engine assembly or ECM.
- RESET MEMORY can be performed only with the Techstream.
HINT:
The ECM learns various conditions and controls the automatic transaxle assembly and engine assembly according to those characteristics. Therefore, when the automatic transaxle assembly, engine assembly, or ECM has been replaced, it is necessary to reset the memory so that the ECM can re-learn. Reset procedure is as follows.
- Turn the ignition switch off.
- Connect the Techstream to the DLC3.
- Turn the ignition switch to ON and the Techstream on.
- Enter the following menus: Powertrain / Engine and ECT / Utility / Reset Memory. Then, press "Next".CAUTION: After performing RESET MEMORY, be sure to perform the ROAD TEST (See ROAD TEST ) described earlier.
HINT:
The ECM learns when the ROAD TEST is performed.
- RESET MEMORY (U250E Automatic Transaxle System) NOTE:
- Perform RESET MEMORY (AT initialization) when replacing the automatic transaxle assembly, engine assembly or ECM.
- RESET MEMORY can be performed only with the Techstream.
HINT:
The ECM learns various conditions and controls the automatic transaxle assembly and engine assembly according to those characteristics. Therefore, when the automatic transaxle assembly, engine assembly, or ECM has been replaced, it is necessary to reset the memory so that the ECM can re-learn. Reset procedure is as follows.
- Turn the ignition switch off.
- Connect the Techstream to the DLC3.
- Turn the ignition switch to ON and the Techstream on.
- Enter the following menus: Powertrain / Engine and ECT / Utility / Reset Memory. Then, press "Next".CAUTION: After performing RESET MEMORY, be sure to perform the ROAD TEST (See ROAD TEST ) described earlier.
HINT:
The ECM learns when the ROAD TEST is performed.
- RESET MEMORY (U341E Automatic Transaxle System) NOTE:
- Perform RESET MEMORY (AT initialization) when replacing the automatic transaxle assembly, engine assembly or ECM.
- RESET MEMORY can be performed only with the Techstream.
HINT:
The ECM learns various conditions and controls the automatic transaxle assembly and engine assembly according to those characteristics. Therefore, when the automatic transaxle assembly, engine assembly, or ECM has been replaced, it is necessary to reset the memory so that the ECM can re-learn. Reset procedure is as follows.
- Turn the ignition switch off.
- Connect the Techstream to the DLC3.
- Turn the ignition switch to ON and the Techstream on.
- Enter the following menus: Powertrain / Engine and ECT / Utility / Reset Memory. Then, press "Next".CAUTION: After performing RESET MEMORY, be sure to perform the ROAD TEST (See ROAD TEST ) described earlier.
HINT:
The ECM learns when the ROAD TEST is performed.
- DESCRIPTION OF CODE REGISTRATION (Tire Pressure Warning System)
It is necessary to register the transmitter IDs in the tire pressure warning ECU when replacing a tire pressure warning valve and transmitter and/or a tire pressure warning ECU.
Prepare all transmitter ID data before starting registration.
- Before registration
- When replacing the tire pressure warning ECU:
- Read the registered transmitter IDs that are stored in the old ECU using the Techstream and note them down.
- If reading stored transmitter IDs is impossible due to malfunctions of components such as the tire pressure warning antenna and receiver, remove the tires from the wheels and check the IDs located on the tire pressure warning valve and transmitters (See TIRE PRESSURE WARNING SYSTEM ).
- When replacing a tire pressure warning valve and transmitter:
- Make a note of the 7-digit number (transmitter ID) written on the tire pressure warning valve and transmitter.
- When replacing the tire pressure warning ECU:
- Before registration
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
