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Mitsubishi U3EFF

06 or U3D01-06) i n the ECM or PHEV-ECU, respectively. Remember to perform the Compulsion Boot Mode in the module where the DTC is present

DriveNot yet established by verified evidence.
ChargeNot yet established by verified evidence.
ServiceService evaluation is appropriate because the supplied manufacturer communication specifies a module boot procedure. The evidence does not establish whether service is mandatory.
Confidence95%

Quick answer

For certain 2023–2024 Mitsubishi Outlander Plug-In Hybrid vehicles, NHTSA manufacturer communication TECH TALK 287 identifies U3EFF-06 in the ECM as a DTC to look for when the 12V auxiliary battery has completely discharged. It instructs technicians to perform Compulsion Boot Mode in the module where the DTC is present.

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 U3EFF mean?

For certain 2023–2024 Mitsubishi Outlander Plug-In Hybrid vehicles, NHTSA manufacturer communication TECH TALK 287 identifies U3EFF-06 in the ECM as a DTC to look for when the 12V auxiliary battery has completely discharged. It instructs technicians to perform Compulsion Boot Mode in the module where the DTC is present.

2. Technical explanation

The supplied official manufacturer communication associates U3EFF-06 with a fully discharged 12V auxiliary battery condition in a 2023–2024 Outlander Plug-In Hybrid. The communication specifically distinguishes U3EFF-06 in the ECM from U3D01-06 in the PHEV-ECU. The supplied evidence does not establish a standalone plain-language definition for U3EFF without the “-06” suffix.

3. What system is affected?

Engine Control Module (ECM), based on the supplied manufacturer communication.

4. How serious is this code?

Unknown. Severity is not established by the verified evidence.

5. Symptoms you may notice

  • A completely discharged 12V auxiliary battery is the condition identified in the supplied manufacturer communication.
  • Other symptoms are not yet established by verified evidence.

6. Possible causes

  • A completely discharged 12V auxiliary battery is identified as the condition under which the communication says to look for U3EFF-06.
  • Any underlying cause of the 12V battery discharge is 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

  • Do not attempt high-voltage repairs.
  • If U3EFF-06 is present, have a Mitsubishi-qualified service facility evaluate the vehicle and follow the applicable manufacturer procedure.
  • Record whether the 12V auxiliary battery was completely discharged before the DTC was found.

10. Step-by-step troubleshooting

  1. Verify whether U3EFF-06 is stored in the ECM.
  2. Verify whether the 12V auxiliary battery was completely discharged.
  3. The manufacturer communication directs technicians to perform Compulsion Boot Mode in the module where the DTC is present.
  4. Further diagnostic steps are not yet established by verified evidence.

11. When to contact service

Service evaluation is appropriate because the supplied manufacturer communication specifies a module boot procedure. The evidence does not establish whether service is mandatory.

12. What the service center may check

  • Check for U3EFF-06 in the ECM.
  • Assess the documented condition of the 12V auxiliary battery discharge.
  • Perform Compulsion Boot Mode in the module where the DTC is present, as directed by TECH TALK 287.

13. Possible repair or resolution

  • The supplied evidence identifies Compulsion Boot Mode in the affected module as a required procedural action when the DTC is present.
  • A completed repair or root-cause resolution is not yet established by verified evidence.

14. Affected vehicles

15. Related TSBs / service bulletins

  • NHTSA Manufacturer Communication PDF 11021739, TECH TALK 287, published July 24, 2025. It identifies U3EFF-06 in the ECM as a DTC to check when the 12V auxiliary battery completely discharges in a 2023–2024 Outlander Plug-In Hybrid, and directs Compulsion Boot Mode in the module where the DTC is present.

16. Recall information

  • No recall information was supplied or established by verified evidence.

17. Official manufacturer information

Official source: NHTSA Manufacturer Communication PDF 11021739, TECH TALK 287: https://static.nhtsa.gov/odi/tsbs/2025/MC-11021739-0001.pdf

19. Frequently asked questions

What does U3EFF-06 indicate on a Mitsubishi Outlander Plug-In Hybrid?

The supplied manufacturer communication identifies U3EFF-06 as a DTC to look for in the ECM when the 12V auxiliary battery has completely discharged. A fuller code definition is not established by the supplied evidence.

Which Mitsubishi vehicles are covered by the supplied evidence?

The diagnostic database applicability lists US-market Mitsubishi Outlander model years 2022–2025. The cited TECH TALK 287 evidence specifically refers to 2023–2024 Outlander Plug-In Hybrid vehicles.

What does Mitsubishi direct technicians to do?

TECH TALK 287 directs technicians to perform Compulsion Boot Mode in the module where the DTC is present.

Is it safe to drive or charge with U3EFF-06?

Not yet established by verified evidence.

20. Sources & verification

Verified
Mitsubishi U3EFF: 06 or U3D01-06) i n the ECM or PHEV-ECU,… | EV Diagnostics