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Kia P1B77

Charging fault) and MCU communication logic

DriveNot yet established by verified evidence.
ChargeNot yet established by verified evidence.
ServiceContact a Kia dealer or qualified EV service provider for diagnosis and to check applicability of TSB ELE192/ELE192_R1.
Confidence95%

Quick answer

For certain U.S.-market 2017–2019 Kia Optima vehicles, DTC P1B77 is identified in Kia TSB ELE192/ELE192_R1 as a High Voltage Battery Pre-Charging fault. The bulletin addresses BMS diagnosis logic, OPU judgment logic for P1B77, and MCU communication logic.

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 P1B77 mean?

For certain U.S.-market 2017–2019 Kia Optima vehicles, DTC P1B77 is identified in Kia TSB ELE192/ELE192_R1 as a High Voltage Battery Pre-Charging fault. The bulletin addresses BMS diagnosis logic, OPU judgment logic for P1B77, and MCU communication logic.

2. Technical explanation

Verified NHTSA-hosted Kia manufacturer communications TSB_ELE192 and TSB_ELE192_R1 state that an update was provided for vehicles produced from August 25, 2016 through September 13, 2018 to improve BMS diagnosis logic, OPU judgment logic for DTC P1B77 (High Voltage Battery Pre-Charging fault), and MCU communication logic. The supplied evidence does not establish a component-level failure cause or a specific repair beyond the bulletin’s stated logic-improvement purpose.

3. What system is affected?

High-voltage battery pre-charging, Battery Management System (BMS) diagnostic logic, OPU judgment logic, and MCU communication logic.

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 identifies diagnostic/judgment and communication logic as the subject of an update.
  • A component-level cause of P1B77 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 Kia dealer or qualified EV service provider.
  • Do not attempt high-voltage battery, BMS, OPU, or MCU repairs yourself.

10. Step-by-step troubleshooting

  1. Have a service provider confirm the stored DTC and determine whether Kia TSB ELE192 or ELE192_R1 applies to the vehicle.
  2. Confirm vehicle eligibility using the vehicle identification number, production date, market, and the complete bulletin instructions.

11. When to contact service

Contact a Kia dealer or qualified EV service provider for diagnosis and to check applicability of TSB ELE192/ELE192_R1.

12. What the service center may check

  • Confirm DTC P1B77.
  • Check whether the vehicle is a U.S.-market 2017–2019 Kia Optima.
  • Verify production date; the bulletin evidence references August 25, 2016 through September 13, 2018.
  • Review Kia TSB ELE192 or revised TSB ELE192_R1 for the applicable procedure.

13. Possible repair or resolution

  • Kia TSB ELE192/ELE192_R1 is described as improving BMS diagnosis logic, OPU judgment logic for P1B77, and MCU communication logic.
  • The exact service procedure and final repair outcome are not established by the supplied evidence.

14. Affected vehicles

15. Related TSBs / service bulletins

  • Kia TSB ELE192, NHTSA Manufacturer Communication 10174515, published April 2, 2020.
  • Kia TSB ELE192_R1, NHTSA Manufacturer Communication 10230492, published January 18, 2023.

16. Recall information

  • No recall is established by the supplied verified evidence.

17. Official manufacturer information

Official NHTSA-hosted Kia communications: https://static.nhtsa.gov/odi/ffdd/tsbs/TSBS_RECEIVED_2020-2024.zip#nhtsa_id=10174515 and https://static.nhtsa.gov/odi/ffdd/tsbs/TSBS_RECEIVED_2020-2024.zip#nhtsa_id=10230492

19. Frequently asked questions

What does Kia P1B77 mean?

The supplied Kia bulletin evidence identifies P1B77 as a High Voltage Battery Pre-Charging fault.

Which vehicles are covered by the available evidence?

The supplied applicability data identifies U.S.-market 2017–2019 Kia Optima vehicles. The bulletin evidence references vehicles produced from August 25, 2016 through September 13, 2018; VIN-based confirmation is required.

Is there a Kia service bulletin for P1B77?

Yes. The supplied evidence identifies Kia TSB ELE192 and revised TSB ELE192_R1, addressing BMS diagnosis logic, OPU judgment logic for P1B77, and MCU communication logic.

Is it safe to drive or charge with P1B77?

Not yet established by verified evidence.

20. Sources & verification

Verified
Kia P1B77: Charging fault) and MCU communication logic | EV Diagnostics