Toyota U0100
2021 model year Highlander, Highlander Hybrid, RAV4, and RAV4 Hybrid; and 2021 model year RAV4 Prime vehicles equipped with Premium Audio (version 1383) may experience the
Quick answer
For certain Toyota vehicles with Premium Audio version 1383, U0100 may be stored intermittently as part of an audio head unit software concern covered by Toyota T-SB-0019-21 Rev. The supplied evidence does not establish a diagnosis for every vehicle with U0100.
This page separates verified manufacturer/regulator evidence from supporting material. Unsupported causes, repairs or safety conclusions are not guessed.
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1. What does U0100 mean?
For certain Toyota vehicles with Premium Audio version 1383, U0100 may be stored intermittently as part of an audio head unit software concern covered by Toyota T-SB-0019-21 Rev. The supplied evidence does not establish a diagnosis for every vehicle with U0100.
2. Technical explanation
Toyota’s bulletin evidence identifies intermittent U0100 among several DTCs that may occur with specified Premium Audio software. The bulletin describes an Audio Head Unit Software Update (Denso-Ten). The supplied evidence does not define the full code meaning, communication path, or a component-level fault diagnosis for U0100.
3. What system is affected?
Premium Audio / Denso-Ten audio head unit software, where applicable under Toyota T-SB-0019-21 Rev.
4. How serious is this code?
Not yet established by verified evidence.
5. Symptoms you may notice
- Abnormal charging icon operation on the charging screen.
- Audio information is not displayed on the meter “Audio” tab.
- Delay when turning off HVAC “AUTO” from the multimedia screen.
- HVAC settings display differently since the last ACC-OFF.
- HVAC blower motor operation is not displayed when in “AUTO.”
- Bluetooth does not reconnect after an Android Auto phone call.
- Bluetooth audio plays after connecting and disconnecting Android Auto.
- Intermittent U0100 may be stored.
6. Possible causes
- For the vehicles and conditions addressed by Toyota T-SB-0019-21 Rev, the verified evidence identifies an audio head unit software concern and provides an Audio Head Unit Software Update.
- Other causes of U0100 are not yet established by verified evidence.
7. Can I still drive the vehicle?
Not yet established by verified evidence.
8. Can I charge the vehicle?
Not yet established by verified evidence.
9. What you can safely do
- Record the symptoms, whether U0100 is intermittent, and any multimedia, HVAC-display, Bluetooth, meter-audio, or charging-icon concerns.
- Have a Toyota dealer or qualified service provider check whether Toyota T-SB-0019-21 Rev applies to the vehicle and installed Premium Audio software.
- Do not attempt high-voltage system repairs based on this code or bulletin evidence.
10. Step-by-step troubleshooting
- Confirm the vehicle model year, model, market, audio-system configuration, and installed Premium Audio software version.
- Check for the symptom set and intermittent DTCs described in Toyota T-SB-0019-21 Rev.
- Determine through Toyota service procedures whether the Audio Head Unit Software Update applies.
11. When to contact service
Contact a Toyota dealer or qualified service provider to verify applicability of Toyota T-SB-0019-21 Rev and evaluate intermittent U0100 in the context of the listed infotainment-related symptoms.
12. What the service center may check
- Verify whether the vehicle is within the models, years, and Premium Audio version addressed by Toyota T-SB-0019-21 Rev.
- Check for intermittent U0100 and the other DTCs listed in the bulletin.
- Assess whether the documented Audio Head Unit Software Update is applicable.
13. Possible repair or resolution
- Toyota T-SB-0019-21 Rev documents an Audio Head Unit Software Update (Denso-Ten) for the covered concern.
- The exact repair outcome for an individual vehicle is not yet established by verified evidence.
14. Affected vehicles
- Toyota Prius Prime · 2021–2022 · US
- Toyota Prius Prime · 2021 · US
- Toyota RAV4 Prime · 2021–2022 · US
- Toyota RAV4 Prime · 2021 · US
15. Related TSBs / service bulletins
- Toyota T-SB-0019-21 Rev, titled “Audio Head Unit Software Update (Denso-Ten),” is documented by NHTSA manufacturer communication PDFs MC-10204562-9999 and MC-10201369-9999.
- The supplied bulletin summaries list intermittent U0100 together with U1110, U0129, U0198, U0265, and U0164.
16. Recall information
- No recall information is established by the supplied verified evidence.
17. Official manufacturer information
NHTSA manufacturer communication: Toyota T-SB-0019-21 Rev. https://static.nhtsa.gov/odi/tsbs/2021/MC-10204562-9999.pdf
19. Frequently asked questions
Is U0100 covered by a Toyota bulletin?
Toyota T-SB-0019-21 Rev lists intermittent U0100 among DTCs associated with an Audio Head Unit Software Update for specified vehicles and Premium Audio software conditions.
Does this evidence prove the audio head unit is defective?
No. The supplied evidence identifies a software-update bulletin, but does not establish a defective component for every U0100 occurrence.
Which vehicles are identified in the supplied applicability data?
The supplied applicability data lists US-market 2021 Prius Prime, 2021–2022 Prius Prime, 2021 RAV4 Prime, and 2021–2022 RAV4 Prime entries. The bulletin summary specifically describes certain 2021 RAV4 Prime vehicles with Premium Audio version 1383; model-year and configuration applicability should be verified by Toyota service.