Mitsubishi P1AAB
Is the diagnostic trouble code stored? YES : Replace the Main Drive Lithium-ion Battery. NO : The diagnosis is complete. Code No. P1AB5: CMU01 module temperature abnormal (low inpu
Quick answer
For the listed Mitsubishi i-MiEV applications, verified Mitsubishi service-bulletin evidence directs technicians to check whether DTC P1AAB is stored in the BMU using scan tool MB991958 and the BMU “CMU ID numbering” special function. If P1AAB is stored, the bulletin directs replacement of the Main Drive Lithium-ion Battery. If it is not stored, that diagnostic path is complete.
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 P1AAB mean?
For the listed Mitsubishi i-MiEV applications, verified Mitsubishi service-bulletin evidence directs technicians to check whether DTC P1AAB is stored in the BMU using scan tool MB991958 and the BMU “CMU ID numbering” special function. If P1AAB is stored, the bulletin directs replacement of the Main Drive Lithium-ion Battery. If it is not stored, that diagnostic path is complete.
2. Technical explanation
The available verified evidence is an official Mitsubishi manufacturer communication filed with NHTSA: TSB-19-54-003 and TSB-19-54-004, published March 13, 2019. In the cited diagnostic sequence, after an earlier EV-ECU check for P1B30, the technician uses scan tool MB991958, selects “CMU ID numbering” on the BMU special-function screen, and checks whether P1AAB is stored in the BMU. The documented decision is: P1AAB stored—replace the Main Drive Lithium-ion Battery; P1AAB not stored—the diagnosis is complete. The supplied excerpt does not establish a fuller plain-language fault definition for P1AAB.
3. What system is affected?
Main Drive Lithium-ion Battery and BMU diagnostic process. The supplied evidence also references CMU ID numbering.
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
- The verified bulletin evidence establishes a diagnostic decision path for stored P1AAB, but does not establish a specific underlying component-level cause beyond its instruction to replace the Main Drive Lithium-ion Battery when P1AAB is stored.
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 Mitsubishi-qualified EV service facility.
- Do not attempt high-voltage battery diagnosis, disassembly, or replacement yourself.
- Provide the service facility with the stored code and the applicable NHTSA manufacturer communication references.
10. Step-by-step troubleshooting
- A technician follows the bulletin’s preceding diagnostic sequence, including checking whether P1B30 is stored in the EV-ECU.
- Using scan tool MB991958, select “CMU ID numbering” on the BMU special-function screen and execute it.
- Check whether P1AAB is stored in the BMU.
- If P1AAB is stored, the bulletin directs replacement of the Main Drive Lithium-ion Battery.
- If P1AAB is not stored, the bulletin states that the diagnosis is complete.
11. When to contact service
Contact a Mitsubishi-qualified EV service facility for diagnosis. The verified procedure requires scan tool MB991958 and BMU special-function access.
12. What the service center may check
- Check for DTC P1B30 in the EV-ECU as part of the cited bulletin sequence.
- Use scan tool MB991958.
- Execute the BMU “CMU ID numbering” special function.
- Confirm whether P1AAB is stored in the BMU.
13. Possible repair or resolution
- When P1AAB is stored in the BMU during the documented procedure, replace the Main Drive Lithium-ion Battery.
- When P1AAB is not stored, the cited diagnostic path is complete.
14. Affected vehicles
- Mitsubishi i-MiEV · 2012 · US
- Mitsubishi i-MiEV · 2014 · US
15. Related TSBs / service bulletins
- Mitsubishi TSB-19-54-003, published March 13, 2019; NHTSA manufacturer communication MC-10158408. Verified evidence includes the P1AAB BMU check and the Main Drive Lithium-ion Battery replacement direction if the code is stored.
- Mitsubishi TSB-19-54-004, published March 13, 2019; NHTSA manufacturer communication MC-10158409. Verified evidence includes the P1AAB BMU check and the Main Drive Lithium-ion Battery replacement direction if the code is stored.
16. Recall information
No recall relationship is established by verified evidence.
17. Official manufacturer information
Official NHTSA-hosted manufacturer communications: https://static.nhtsa.gov/odi/tsbs/2019/MC-10158408-9999.pdf and https://static.nhtsa.gov/odi/tsbs/2019/MC-10158409-9999.pdf. Verified applicability supplied: 2012 and 2014 Mitsubishi i-MiEV, U.S. market.
19. Frequently asked questions
What does the verified procedure say to do if P1AAB is stored?
The cited Mitsubishi bulletin directs replacement of the Main Drive Lithium-ion Battery.
What if P1AAB is not stored?
The cited diagnostic path states that the diagnosis is complete.
How is P1AAB checked in the bulletin?
The bulletin instructs use of scan tool MB991958, selection of “CMU ID numbering” on the BMU special-function screen, and confirmation of whether P1AAB is stored in the BMU.
Which vehicles are established by the supplied evidence?
U.S.-market 2012 and 2014 Mitsubishi i-MiEV vehicles.