MG

Moderator
Please see T-SB-0070-21

Applicability:

2021 Toyota Venza Hybrid

Introduction:
Some 2021 model year Venza Hybrid vehicles may exhibit a depleted 12V auxiliary battery when in IG-OFF due to a condition in which the Hybrid Vehicle Electronic Control Unit (HV ECU) does not sleep. The HV ECU may not sleep if any of the following conditions have occurred with the vehicle:

* The vehicle was towed or jump-started after a 12V battery discharge.
* The vehicle’s 12V battery was disconnected and reconnected, as when accessories were installed.
* The 12V battery terminal(s) or power or ground harnesses were removed to repair the vehicle.
* A new 12V battery was put into the vehicle, or there was an open in the main fusible link.
* Any other condition that may have caused power not properly flowing from the 12V battery through the harness.

The HV ECU logic has been updated to reduce the possibility of this condition. Follow the Repair Procedure in this bulletin to address this condition.

NOTICE:
The condition in which the HV ECU does not sleep with resulting discharge of 12V battery may be a secondary condition when other primary causes for low 12V battery voltage occur. The primary cause of low 12V battery conditions will need to be addressed BEFORE completing the procedures outlined in this Service Bulletin.

Warranty Information:
Hybrid Vehicle Control Computer Reprogramming

APPLICABLE WARRANTY:
This repair is covered under the Toyota Hybrid Warranty. This warranty is in effect for 96 months or 100,000 miles, whichever occurs first, from the vehicle’s in-service date. Warranty application is limited to occurrence of the specified condition described in this bulletin.

Repair Procedure:
1. Has the vehicle exhibited a depleted 12V auxiliary battery?

NOTICE:
The HV ECU may not sleep if ANY of the following have occurred with the vehicle:
* The vehicle was towed or jump-started after a 12V battery discharge.
* The vehicle’s 12V battery was disconnected and reconnected, as when accessories were installed.
* The 12V battery terminal(s) or power or ground harnesses were removed to repair the vehicle.
* A new 12V battery was put into the vehicle, or there was an open in the main fusible link.
* Any other condition that may have caused power not properly flowing from the 12V battery through the harness. Ensure these are addressed before continuing to step 2.

YES — Continue to step 2.
NO — This bulletin does NOT apply. Continue diagnosis using the applicable Repair Manual.

2. Use Techstream to confirm if the HV ECU calibration has been updated and check for the Authorized Modifications Label affixed to the vehicle in the location shown below. Is the calibration ID listed in Techstream and on the label the latest HV ECU calibration?
YES — This bulletin does NOT apply. Continue diagnosis using the applicable Repair Manual.
NO — Continue to step 3.

3. Flash reprogram the HV ECU

4. Prepare and install the Authorized Modifications Label.

5. Test-drive the vehicle to confirm proper operation
 
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