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Tesla BMS_u018

Maximum battery charge level reduced OK to drive - Schedule service

Common search variants: BMSu018 · BMS-u018 · BMS u018 · Search ignores case and common separators.

DriveYes, according to the documented alert wording: “OK to drive.”
ChargeCharging availability is not yet established by verified evidence. Verified documentation establishes that the maximum charge level is reduced.
ServiceSchedule Tesla service at the earliest convenience if BMS_u018 persists. Tesla documentation states that service is required to restore full performance.
Confidence95%

Quick answer

BMS_u018 means the vehicle detected a condition internal to the high-voltage battery that limits battery performance. Maximum charge level and driving range are reduced. Tesla’s documented instruction is to schedule service if the alert persists.

This page separates verified manufacturer/regulator evidence from supporting material. Unsupported causes, repairs or safety conclusions are not guessed.

Video guides

Watch Videos

Relevant videos play here without leaving this diagnostic page.

How to diagnose and fix Tesla #BMS_u018_SOC_Imbalance_Limiting Maximum battery charge level reducedDigital EV Doctor (Tesla alert clear)
Tesla "Voltage Harness Sense" BMS_w107 BMS_w177 BMS_a129 alerts clear #BMS_u018 #VSHDigital EV Doctor (Tesla alert clear)
Clear Tesla Maximum Battery Charge Level Reduced BMS_u029 BMS_u018 alert #BMS_u029 #BMS_u018Digital EV Doctor (Tesla alert clear)

Videos are supporting material and never override OEM or regulator evidence.

1. What does BMS_u018 mean?

BMS_u018 means the vehicle detected a condition internal to the high-voltage battery that limits battery performance. Maximum charge level and driving range are reduced. Tesla’s documented instruction is to schedule service if the alert persists.

2. Technical explanation

Tesla documentation submitted to NHTSA states that BMS_u018 is: “Maximum battery charge level reduced OK to drive - Schedule service.” The alert indicates a condition internal to the high-voltage battery that is limiting performance. The documented results are a reduced maximum charge level and reduced range; service is required to restore full performance.

3. What system is affected?

High-voltage battery / battery-management system.

4. How serious is this code?

The database severity field is unknown. Verified Tesla documentation states that battery performance, maximum charge level, and range are reduced, and that service is required to restore full performance.

5. Symptoms you may notice

  • BMS_u018 alert displayed.
  • Reduced maximum battery charge level.
  • Reduced driving range.

6. Possible causes

  • A condition internal to the high-voltage battery is limiting battery performance. A more specific underlying cause is not yet established by verified evidence.

7. Can I still drive the vehicle?

Yes, according to the documented alert wording: “OK to drive.”

8. Can I charge the vehicle?

Charging availability is not yet established by verified evidence. Verified documentation establishes that the maximum charge level is reduced.

9. What you can safely do

  • Plan for reduced available range and reduced maximum charge level.
  • Schedule Tesla service if the alert persists.
  • Use the vehicle’s displayed battery charge level and range information when planning travel.

10. Step-by-step troubleshooting

  1. No owner-performed diagnostic or repair procedure is established by verified evidence.
  2. Do not attempt high-voltage battery diagnosis, disassembly, or repair.
  3. If the alert persists, schedule service at the earliest convenience, as stated in Tesla documentation.

11. When to contact service

Schedule Tesla service at the earliest convenience if BMS_u018 persists. Tesla documentation states that service is required to restore full performance.

12. What the service center may check

  • Confirm the stored BMS_u018 alert and associated vehicle information.
  • Diagnose the condition internal to the high-voltage battery that is limiting performance. Specific test procedures are not established by verified evidence.

13. Possible repair or resolution

  • Service is required to restore full performance, according to Tesla documentation.
  • The specific repair or component replacement is not yet established by verified evidence.

14. Affected vehicles

15. Related TSBs / service bulletins

  • NHTSA manufacturer communication 10253660, published March 26, 2024: https://static.nhtsa.gov/odi/tsbs/2024/MC-10253660-9999.pdf
  • NHTSA manufacturer communication 10253658, published March 26, 2024: https://static.nhtsa.gov/odi/tsbs/2024/MC-10253658-9999.pdf
  • NHTSA manufacturer communication 10250483, published December 1, 2023: https://static.nhtsa.gov/odi/tsbs/2023/MC-10250483-9999.pdf
  • NHTSA manufacturer communication 10250482, published December 1, 2023: https://static.nhtsa.gov/odi/tsbs/2023/MC-10250482-9999.pdf

16. Recall information

  • No recall information was supplied in the verified evidence.

17. Official manufacturer information

Verified NHTSA-hosted Tesla owner-documentation evidence identifies BMS_u018 and explains that an internal high-voltage-battery condition is limiting performance, reducing maximum charge level and range. Verified applicability: US Tesla Model 3 (2017–2023), Model S (2012–2023), and Model X (2016–2023).

19. Frequently asked questions

What does Tesla BMS_u018 mean?

It means the vehicle detected a condition internal to the high-voltage battery that limits battery performance. Maximum charge level and range are reduced.

Can I drive with BMS_u018?

Yes. The verified alert wording says “OK to drive.”

Will BMS_u018 reduce range?

Yes. Tesla documentation states that range is reduced.

Will the battery charge to its normal maximum level?

No. Tesla documentation states that the maximum charge level is reduced.

Do I need service for BMS_u018?

If the alert persists, Tesla documentation says to schedule service at the earliest convenience. It also states that service is required to restore full performance.

What component has failed?

Not yet established by verified evidence. The documentation identifies only an internal high-voltage-battery condition limiting performance.

20. Sources & verification

Verified
Show all 24 verified sources
Tesla BMS_u018: Maximum battery charge level reduced OK to drive -… | EV Diagnostics