Mitsubishi P1C09
ECU allows the DC-DC converter to operate. Judgment Criterion The rectification area temperature sensor is more than 105 C (221 F). <P1C08> The temperature sensor in the DC-D
Quick answer
P1C09 is a Mitsubishi i-MiEV DC-DC converter internal-temperature fault. Verified criteria: the DC-DC converter internal temperature sensor reports more than 105°C (221°F). The documented fail-safe stops DC-DC converter output.
This page separates verified manufacturer/regulator evidence from supporting material. Unsupported causes, repairs or safety conclusions are not guessed.
Watch Videos
Relevant videos play here without leaving this diagnostic page.
No sufficiently relevant embeddable video has been accepted for this diagnostic yet.
Videos are supporting material and never override OEM or regulator evidence.
1. What does P1C09 mean?
P1C09 is a Mitsubishi i-MiEV DC-DC converter internal-temperature fault. Verified criteria: the DC-DC converter internal temperature sensor reports more than 105°C (221°F). The documented fail-safe stops DC-DC converter output.
2. Technical explanation
For the 2012–2013 US Mitsubishi i-MiEV, NHTSA-published Mitsubishi TSB-20-54-003 identifies P1C09 as “DCDC Inside Temperature.” The trouble judgment requires the EV-ECU to allow DC-DC converter operation and the temperature sensor inside the DC-DC converter to exceed 105°C (221°F). The documented fail-safe/backup function is that DC-DC converter output is stopped.
3. What system is affected?
DC-DC converter and its internal temperature monitoring/cooling-related system.
4. How serious is this code?
Not yet established by verified evidence. However, the verified fail-safe stops DC-DC converter output.
5. Symptoms you may notice
- DC-DC converter output is stopped by the documented fail-safe function.
6. Possible causes
- EV-ECU failure.
- Insufficient coolant.
- Water-pump failure.
- Radiator-fan failure.
- Failure of the temperature sensor installed in the DC-DC converter.
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 component repair based on this information.
10. Step-by-step troubleshooting
- Verified TSB evidence states that diagnosis begins by using scan tool MB991958. Further diagnostic steps are not established by the supplied verified evidence.
11. When to contact service
Service is advisable because P1C09 causes the documented DC-DC converter-output shutdown. The supplied evidence does not establish whether service is mandatory.
12. What the service center may check
- Use scan tool MB991958 as stated in TSB-20-54-003.
- Evaluate the documented probable causes: EV-ECU, coolant quantity, water pump, radiator fan, and the DC-DC converter’s installed temperature sensor.
13. Possible repair or resolution
- Not yet established by verified evidence. The supplied TSB excerpt identifies diagnostic probable causes but does not provide a verified repair outcome.
14. Affected vehicles
- Mitsubishi i-MiEV · 2012–2013 · US
15. Related TSBs / service bulletins
- Mitsubishi TSB-20-54-003, published by NHTSA as Manufacturer Communication PDF 10175779 on 2020-04-22. It documents P1C09 DCDC Inside Temperature, its threshold, fail-safe action, and probable causes.
16. Recall information
- Not yet established by verified evidence.
17. Official manufacturer information
Official source: NHTSA Manufacturer Communication PDF 10175779, Mitsubishi TSB-20-54-003: https://static.nhtsa.gov/odi/tsbs/2020/MC-10175779-9999.pdf
19. Frequently asked questions
What triggers P1C09?
The verified criterion is a DC-DC converter internal temperature sensor reading above 105°C (221°F), while the EV-ECU allows DC-DC converter operation.
What does the vehicle do when P1C09 is set?
The documented fail-safe stops DC-DC converter output.
Which vehicles does this evidence apply to?
The supplied applicability evidence covers US-market 2012–2013 Mitsubishi i-MiEV vehicles.