Mitsubishi U1100
Replace the EV-ECU (Refer to GROUP 54D EV- ECU ). NO : Go to Step 5. STEP 5. Recheck for diagnostic trouble code. Check again if the DTC is set in the on board charger. (1) Erase
Quick answer
For U1100 on a 2012–2013 Mitsubishi i-MiEV (US), verified evidence directs diagnosis through EV-ECU and other-ECU DTC checks, followed by a recheck in the on-board charger after clearing the DTC and performing a regular charge. The bulletin’s indicated repair path may involve EV-ECU replacement or on-board charger/DC-DC converter replacement, depending on test results.
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 U1100 mean?
For U1100 on a 2012–2013 Mitsubishi i-MiEV (US), verified evidence directs diagnosis through EV-ECU and other-ECU DTC checks, followed by a recheck in the on-board charger after clearing the DTC and performing a regular charge. The bulletin’s indicated repair path may involve EV-ECU replacement or on-board charger/DC-DC converter replacement, depending on test results.
2. Technical explanation
NHTSA-hosted Mitsubishi bulletin TSB-20-54-003 describes a diagnostic sequence using scan tool MB991958. It instructs the technician to check for EV-ECU-system DTCs and then determine whether U1100 is set in another ECU. If U1100 is set in another ECU, the bulletin directs replacement of the EV-ECU. If not, it directs a DTC recheck in the on-board charger: erase the DTC, perform a regular charge, and check whether the DTC resets. The supplied evidence excerpt states that, if the DTC is set following that recheck, replacement of the on-board charger/DC-DC converter is directed.
3. What system is affected?
EV-ECU, other ECUs, and the on-board charger/DC-DC converter are referenced in the verified diagnostic procedure.
4. How serious is this code?
Not yet established by verified evidence.
5. Symptoms you may notice
Not yet established by verified evidence.
6. Possible causes
- U1100 set in another ECU, as evaluated in the bulletin’s diagnostic path.
- A DTC that resets in the on-board charger after erasure and a regular charge, as evaluated in the bulletin’s diagnostic path.
- Additional root causes 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
- Arrange diagnosis by a qualified Mitsubishi EV service provider using the applicable diagnostic procedure.
- Do not attempt high-voltage component diagnosis, EV-ECU replacement, or on-board charger/DC-DC converter replacement yourself.
- Record when the code was found and whether it returns after charging, if this information is available without performing repairs.
10. Step-by-step troubleshooting
- Use scan tool MB991958 to check for DTCs in other systems, as specified in TSB-20-54-003.
- Determine whether an EV-ECU-system DTC is set; if so, the bulletin directs checking the EV-ECU system using the EV-ECU DTC inspection chart.
- Determine whether U1100 is set in another ECU. If yes, the bulletin directs EV-ECU replacement.
- If U1100 is not set in another ECU, erase the DTC, perform a regular charge, and check whether the DTC is set again in the on-board charger.
- If the DTC is set after that recheck, the supplied bulletin excerpt directs replacement of the on-board charger/DC-DC converter.
11. When to contact service
Contact a Mitsubishi EV-qualified service provider for diagnosis and repair. The verified procedure calls for scan tool MB991958 and references Mitsubishi EV-ECU service information.
12. What the service center may check
- Check for EV-ECU-system DTCs.
- Check whether U1100 is set in another ECU.
- After DTC erasure and a regular charge, check whether the DTC is set in the on-board charger.
13. Possible repair or resolution
- If U1100 is set in another ECU, TSB-20-54-003 directs replacement of the EV-ECU.
- If the DTC is set in the on-board charger after clearing the DTC and performing a regular charge, the supplied evidence excerpt directs replacement of the on-board charger/DC-DC converter.
- Any further repair outcome is not yet established by verified evidence.
14. Affected vehicles
- Mitsubishi i-MiEV · 2012–2013 · US
15. Related TSBs / service bulletins
- Mitsubishi TSB-20-54-003, published April 22, 2020; NHTSA Manufacturer Communication PDF 10175779. It contains the verified U1100 diagnostic and repair decision path summarized here.
16. Recall information
No recall relationship is established by verified evidence.
17. Official manufacturer information
Official source: NHTSA-hosted Mitsubishi manufacturer communication, TSB-20-54-003 (MC-10175779): https://static.nhtsa.gov/odi/tsbs/2020/MC-10175779-9999.pdf
19. Frequently asked questions
Which vehicles are covered by the supplied applicability data?
The verified applicability data identifies US-market 2012–2013 Mitsubishi i-MiEV vehicles.
Does U1100 automatically mean the EV-ECU must be replaced?
No. The verified bulletin directs EV-ECU replacement when U1100 is set in another ECU. It also includes a separate on-board-charger recheck path.
What does the bulletin require before evaluating whether the on-board-charger DTC returns?
It directs erasing the DTC, performing a regular charge, and then checking whether the DTC is set.
Is it safe to drive or charge with U1100?
Not yet established by verified evidence.