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Mitsubishi P1AA1

CMU ID change (CMU07), P1AA2: CMU ID change (CMU08), P1AA3: CMU ID change (CMU09), P1AA4: CMU ID change (CMU10), P1AA5: CMU ID change (CMU11), P1AA6: CMU ID change (CMU12), . TROUB

DriveNot yet established by verified evidence.
ChargeNot yet established by verified evidence.
ServiceContact a Mitsubishi dealer or qualified EV service provider for diagnosis of the BMU/main drive lithium-ion battery system.
Confidence95%

Quick answer

P1AA1 is a Mitsubishi battery-management diagnostic trouble code for “CMU ID change (CMU07).” Verified applicability is the U.S. 2012 and 2014 Mitsubishi i-MiEV.

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 P1AA1 mean?

P1AA1 is a Mitsubishi battery-management diagnostic trouble code for “CMU ID change (CMU07).” Verified applicability is the U.S. 2012 and 2014 Mitsubishi i-MiEV.

2. Technical explanation

The verified Mitsubishi service-bulletin evidence identifies P1AA1 as “CMU ID change (CMU07).” CMU refers to a cell monitoring unit in the main drive lithium-ion battery/BMU diagnostic material. The supplied evidence also lists P1AA2 through P1AA6 for CMU08 through CMU12, respectively. The evidence excerpt states that the judgment check occurs when CMUs are numbered for identification and references U1925, but it does not provide the complete diagnostic conditions, cause, or repair procedure.

3. What system is affected?

Battery Management Unit (BMU) and main drive lithium-ion battery; specifically the CMU07 identification/ID-change diagnostic.

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

  • A CMU07 ID-change condition is identified by the verified Mitsubishi diagnostic description.
  • The underlying cause 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

  • Avoid attempting any high-voltage battery, BMU, or CMU repair yourself.
  • Have the code evaluated by a Mitsubishi-qualified EV service facility using the applicable factory diagnostic information.

10. Step-by-step troubleshooting

  1. Confirm the stored DTC is P1AA1 and record any accompanying DTCs.
  2. Use the applicable Mitsubishi factory service information for the complete diagnostic procedure. The supplied evidence references U1925 but does not establish its relationship or diagnostic outcome for an individual vehicle.
  3. Do not perform high-voltage battery disassembly or CMU service outside qualified EV service procedures.

11. When to contact service

Contact a Mitsubishi dealer or qualified EV service provider for diagnosis of the BMU/main drive lithium-ion battery system.

12. What the service center may check

  • Verify P1AA1 in the BMU diagnostic record.
  • Check for accompanying DTCs, including U1925 if present.
  • Follow the applicable Mitsubishi factory diagnostic procedure for CMU identification numbering and related BMU diagnostics.

13. Possible repair or resolution

  • Not yet established by verified evidence.

14. Affected vehicles

15. Related TSBs / service bulletins

  • Mitsubishi TSB-19-54-003, published March 13, 2019 (NHTSA manufacturer communication MC-10158408). It includes P1AA1 in the CMU ID-change diagnostic listing.
  • Mitsubishi TSB-19-54-004, published March 13, 2019 (NHTSA manufacturer communication MC-10158409). It includes P1AA1 in the CMU ID-change diagnostic listing.

16. Recall information

No recall relationship is established by verified evidence.

17. Official manufacturer information

Official NHTSA-hosted Mitsubishi communications: TSB-19-54-003: https://static.nhtsa.gov/odi/tsbs/2019/MC-10158408-9999.pdf ; TSB-19-54-004: https://static.nhtsa.gov/odi/tsbs/2019/MC-10158409-9999.pdf

19. Frequently asked questions

What does P1AA1 mean?

Verified Mitsubishi information defines P1AA1 as “CMU ID change (CMU07).”

Which vehicles are verified as applicable?

The supplied verified data establishes applicability to U.S.-market 2012 and 2014 Mitsubishi i-MiEV vehicles.

Is it safe to drive or charge with P1AA1?

Not yet established by verified evidence.

Does P1AA1 identify a failed battery cell or required battery replacement?

Not yet established by verified evidence.

20. Sources & verification

Verified
Mitsubishi P1AA1: CMU ID change (CMU07), P1AA2: CMU ID change (CMU08),… | EV Diagnostics