Mitsubishi P1A31
ECU. Q: Is the diagnostic trouble code stored? YES : Carry out troubleshooting for diagnostic trouble code No. P1A3 0, P1A31 or P1B33. NO : Go to Step 2. STEP 2. Scan tool MB991958
Quick answer
For the 2012 Mitsubishi i-MiEV (US), P1A31 is identified in an official Mitsubishi/NHTSA service bulletin as an EV-ECU diagnostic trouble code that requires its specific diagnostic procedure when stored.
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 P1A31 mean?
For the 2012 Mitsubishi i-MiEV (US), P1A31 is identified in an official Mitsubishi/NHTSA service bulletin as an EV-ECU diagnostic trouble code that requires its specific diagnostic procedure when stored.
2. Technical explanation
Verified evidence states that, during diagnosis, a technician uses scan tool MB991958 to check whether P1A30, P1A31, or P1A33 is stored in the EV-ECU. If P1A31 is stored, the instruction is to carry out troubleshooting for that DTC. The supplied evidence does not establish a component-level definition, failure mechanism, or repair for P1A31.
3. What system is affected?
EV-ECU. The supplied bulletin is within an electric motor unit and main drive lithium-ion battery diagnostic section.
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
- 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
- Have the EV-ECU checked with the specified Mitsubishi scan tool, MB991958, by qualified service personnel.
- Do not attempt high-voltage battery or electric-drive repair based on this code alone.
10. Step-by-step troubleshooting
- Use scan tool MB991958 to check whether P1A30, P1A31, or P1A33 is stored in the EV-ECU.
- If P1A31 is stored, carry out the diagnostic procedure for P1A31 as directed by the Mitsubishi service information.
- The cited procedure also references checking the domestic power supply facility, connecting the regular charging cable, and reviewing scan-tool service data. The supplied evidence does not provide the complete P1A31 decision path or its final diagnostic conclusion.
11. When to contact service
Service is appropriate because the verified procedure calls for Mitsubishi scan tool MB991958 and DTC-specific troubleshooting. Whether service is immediately required is not yet established by verified evidence.
12. What the service center may check
- Confirm stored EV-ECU DTCs with scan tool MB991958.
- Where applicable to the referenced procedure, check the domestic power supply facility and connect the regular charging cable.
- Review service-data Item No. 6, Minimum voltage cell ID.
- Review service-data Item No. 33, Maximum value of cell voltage difference. The bulletin excerpt lists an OK criterion of 0.2 V or less, but the supplied excerpt is incomplete regarding all conditions and next steps.
13. Possible repair or resolution
- Not yet established by verified evidence.
14. Affected vehicles
- Mitsubishi i-MiEV · 2012 · US
15. Related TSBs / service bulletins
- Mitsubishi TSB-19-54-003, published through NHTSA on 2019-03-13 as Manufacturer Communication PDF 10158408. It includes an EV-ECU diagnostic check for P1A30, P1A31, and P1A33 on the covered vehicle application.
16. Recall information
- No recall information was supplied as verified evidence.
17. Official manufacturer information
Official source: NHTSA Manufacturer Communication PDF 10158408, Mitsubishi TSB-19-54-003: https://static.nhtsa.gov/odi/tsbs/2019/MC-10158408-9999.pdf
19. Frequently asked questions
What does P1A31 mean on a 2012 Mitsubishi i-MiEV?
Verified evidence identifies P1A31 as an EV-ECU DTC for which Mitsubishi directs DTC-specific troubleshooting. A more specific fault description is not established by the supplied evidence.
Which vehicle is covered by the supplied evidence?
2012 Mitsubishi i-MiEV, US-market applicability.
Can I continue driving or charging with P1A31?
Not yet established by verified evidence.
What tool does the cited Mitsubishi procedure specify?
Scan tool MB991958.