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Mitsubishi P1AC3

ion batt ery is charged. Judgment Criterion  For more than 5 seconds, the PWM output signal of the main drive lithium-ion ba ttery fan is 100 percent (while the fan stops). The ou

DriveNot yet established by verified evidence.
ChargeNot yet established by verified evidence.
ServiceContact a Mitsubishi-qualified service facility for diagnosis and repair. The supplied official bulletin contains a specific repair direction when P1AC3 is confirmed.
Confidence95%

Quick answer

P1AC3 is documented by Mitsubishi as “Battery Cooling Fan (Rest Fail)” for the 2016 US Mitsubishi i‑MiEV. The cited service bulletin directs technicians to confirm the DTC with scan tool MB991958; if confirmed, replace the main drive lithium-ion battery cooling fan.

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 P1AC3 mean?

P1AC3 is documented by Mitsubishi as “Battery Cooling Fan (Rest Fail)” for the 2016 US Mitsubishi i‑MiEV. The cited service bulletin directs technicians to confirm the DTC with scan tool MB991958; if confirmed, replace the main drive lithium-ion battery cooling fan.

2. Technical explanation

The verified Mitsubishi/NHTSA bulletin defines the setting conditions as the electric motor switch being ON or the main drive lithium-ion battery being charged. The DTC is judged when, for more than 5 seconds, the battery fan PWM command is 100% while the fan is stopped. The source also refers to fan rotational-speed output, but the supplied evidence does not include the complete wording or additional diagnostic thresholds.

3. What system is affected?

Main drive lithium-ion battery cooling fan.

4. How serious is this code?

Not yet established by verified evidence.

5. Symptoms you may notice

  • P1AC3 may be stored when the main drive lithium-ion battery cooling fan is commanded at 100% PWM for more than 5 seconds while stopped.
  • Additional driver-visible symptoms are not yet established by verified evidence.

6. Possible causes

  • Verified bulletin repair direction: a confirmed P1AC3 leads to replacement of the cooling fan in the main drive lithium-ion battery.
  • If the DTC is not present during inspection, the bulletin identifies the condition as an intermittent malfunction.
  • Other causes are 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 vehicle diagnosed with the specified scan tool or equivalent manufacturer-approved service equipment.
  • Avoid attempting high-voltage battery or cooling-fan repair procedures yourself.
  • Record whether the DTC is currently present and provide that information to a Mitsubishi-qualified service facility.

10. Step-by-step troubleshooting

  1. Use scan tool MB991958 to confirm whether P1AC3 is set, as directed in TSB-19-54-005.
  2. If P1AC3 is set, the bulletin directs replacement of the main drive lithium-ion battery cooling fan.
  3. If P1AC3 is not set, the bulletin directs intermittent-malfunction troubleshooting under Mitsubishi Group 00 procedures.

11. When to contact service

Contact a Mitsubishi-qualified service facility for diagnosis and repair. The supplied official bulletin contains a specific repair direction when P1AC3 is confirmed.

12. What the service center may check

  • Confirm P1AC3 using scan tool MB991958.
  • Determine whether the DTC is currently set.
  • If not set, follow the manufacturer’s intermittent-malfunction diagnostic process referenced in the bulletin.

13. Possible repair or resolution

  • When P1AC3 is confirmed, replace the cooling fan in the main drive lithium-ion battery, per Mitsubishi TSB-19-54-005.
  • The source references service manual procedure P.54D-211 for the fan replacement.

14. Affected vehicles

15. Related TSBs / service bulletins

  • Mitsubishi TSB-19-54-005, published March 13, 2019; NHTSA Manufacturer Communication PDF 10158410 (MC-10158410-9999.pdf). It includes P1AC3 Battery Cooling Fan (Rest Fail) diagnosis and directs cooling-fan replacement when the DTC is confirmed.

16. Recall information

  • Not yet established by verified evidence.

17. Official manufacturer information

Official source: NHTSA-hosted Mitsubishi Manufacturer Communication PDF 10158410, TSB-19-54-005: https://static.nhtsa.gov/odi/tsbs/2019/MC-10158410-9999.pdf

19. Frequently asked questions

What does P1AC3 mean on a 2016 Mitsubishi i‑MiEV?

The verified Mitsubishi bulletin identifies P1AC3 as “Battery Cooling Fan (Rest Fail).”

When can P1AC3 set?

According to the bulletin, it can set with the electric motor switch ON or while the main drive lithium-ion battery is being charged, when the fan PWM output is 100% for more than 5 seconds while the fan is stopped.

What is the specified repair if P1AC3 is confirmed?

The bulletin directs replacement of the cooling fan in the main drive lithium-ion battery.

Can I drive or charge with P1AC3?

Not yet established by verified evidence.

20. Sources & verification

Verified
Mitsubishi P1AC3: ion batt ery is charged. Judgment Criterion  For… | EV Diagnostics