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Mitsubishi P1C21

DCDC Input Voltage Abnormal (2) . TROUBLE JUDGMENT Check Conditions  The EV-ECU allows the DC-DC converter to operate. Judgment Criterion  The system detects a failure "overvolta

DriveNot yet established by verified evidence.
ChargeNot yet established by verified evidence.
ServiceContact a qualified Mitsubishi EV service provider for diagnosis. The official bulletin’s directed repair path, when P1C21 is confirmed set, is replacement of the onboard charger/DC-DC converter.
Confidence95%

Quick answer

P1C21 is a Mitsubishi i-MiEV diagnostic trouble code for “DCDC Input Voltage Abnormal (2).” Verified evidence says the EV-ECU detects a fault in the DC-DC converter input-section overvoltage-abnormal-detection circuit for a predetermined time or longer, and the DC-DC converter output is stopped.

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 P1C21 mean?

P1C21 is a Mitsubishi i-MiEV diagnostic trouble code for “DCDC Input Voltage Abnormal (2).” Verified evidence says the EV-ECU detects a fault in the DC-DC converter input-section overvoltage-abnormal-detection circuit for a predetermined time or longer, and the DC-DC converter output is stopped.

2. Technical explanation

The verified Mitsubishi service bulletin describes P1C21 as DCDC Input Voltage Abnormal (2). The check condition is that the EV-ECU permits DC-DC converter operation. The judgment criterion is detection of a failure in the input-section “overvoltage abnormal detection circuit” by predetermined times or more. The documented fail-safe/backup function is that DC-DC converter output stops.

3. What system is affected?

DC-DC converter and its input-section overvoltage-abnormal-detection circuit; EV-ECU monitoring/control.

4. How serious is this code?

Not yet established by verified evidence.

5. Symptoms you may notice

  • The DC-DC converter output is stopped when the fault is detected.

6. Possible causes

  • Verified evidence identifies a failure in the DC-DC converter input-section overvoltage-abnormal-detection circuit as the judgment basis.
  • The specific underlying component-level 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

  • Arrange diagnosis by a qualified Mitsubishi EV service provider.
  • Do not attempt high-voltage diagnosis, removal, or repair of the onboard charger/DC-DC converter yourself.

10. Step-by-step troubleshooting

  1. The cited Mitsubishi bulletin instructs technicians to check whether P1C21 is set after the specified procedure.
  2. If P1C21 is set, the bulletin directs replacement of the onboard charger/DC-DC converter, referring to the OBC Removal & Installation procedure in the bulletin.
  3. If P1C21 is not set, the bulletin identifies the condition as an intermittent malfunction and refers to Mitsubishi intermittent-malfunction troubleshooting guidance.

11. When to contact service

Contact a qualified Mitsubishi EV service provider for diagnosis. The official bulletin’s directed repair path, when P1C21 is confirmed set, is replacement of the onboard charger/DC-DC converter.

12. What the service center may check

  • Confirm whether DTC P1C21 is set using the manufacturer diagnostic procedure.
  • If the code is confirmed, follow the official OBC/DC-DC converter removal and installation procedure referenced in TSB-20-54-003.
  • If the code does not reset, evaluate as an intermittent malfunction using the manufacturer’s intermittent-malfunction guidance.

13. Possible repair or resolution

  • For a confirmed P1C21, TSB-20-54-003 directs replacement of the onboard charger/DC-DC converter.
  • If P1C21 is not set during the bulletin procedure, the bulletin classifies it as an intermittent malfunction rather than directing component replacement.

14. Affected vehicles

15. Related TSBs / service bulletins

  • Mitsubishi TSB-20-54-003, published April 22, 2020; NHTSA Manufacturer Communication PDF 10175779 (MC-10175779-9999). It documents P1C21 and directs replacement of the onboard charger/DC-DC converter if the DTC is confirmed set.

16. Recall information

  • Not yet established by verified evidence.

17. Official manufacturer information

Official source: NHTSA-hosted Mitsubishi Manufacturer Communication, TSB-20-54-003: https://static.nhtsa.gov/odi/tsbs/2020/MC-10175779-9999.pdf

19. Frequently asked questions

What does P1C21 mean?

It means “DCDC Input Voltage Abnormal (2)” in the verified Mitsubishi bulletin.

What happens when P1C21 is detected?

The verified fail-safe function is that DC-DC converter output is stopped.

What vehicle applicability is verified?

Verified applicability is the 2012–2013 Mitsubishi i-MiEV in the United States.

What repair does the official bulletin direct?

If P1C21 is confirmed set using the bulletin procedure, it directs replacement of the onboard charger/DC-DC converter.

20. Sources & verification

Verified
Mitsubishi P1C21: DCDC Input Voltage Abnormal (2) . TROUBLE JUDGMENT… | EV Diagnostics