P1B77

A model year appears here because the code is named in its record, not because every one of these vehicles sets it. Counts are mentions in the federal files, not failure rates — nobody publishes the denominator.

Service bulletins and campaigns whose filed summary names P1B77. Quoting the document number at a service desk is often the fastest route to a diagnosis someone has already written down.

• TSB_ELE364
  2024-12-23 · Fuel/Propulsion System
• TECHNICAL SERVICE BULLETIN: SERVICE ACTION: MOTOR CONTROL UNIT (MCU) LOGIC IMPROVEMENT (SA596) - This bulletin provides the procedure to update the Motor Control Unit (MCU) software on certain 2025MY Sorento HEV (MQ4 HEV) vehicles equipped with 19â€� wheels and produced from March 4, 2024 through November 9, 2024. The affected vehicles may exhibit traction motor noise, an inoperable A/C, and illum
• 24-EV-004G
  2024-07-12 · Electrical System
• This bulletin provides important special service instructions to properly repair a vehicle that has been diagnosed to require an Integrated Charge Control Unit (ICCU) replacement, such as required for DTC P1A9096 DC to DC related charging concern or for inoperative AC charging. • The ICCU fuse accessible from a rear side panel of the EV Battery, should NEVER be replaced by itself prior to receivin
• 24-EV-004H
  2024-07-12 · Electrical System
• This bulletin provides important special service instructions to properly repair a vehicle that has been diagnosed to require an Integrated Charge Control Unit (ICCU) replacement, such as required for DTC P1A9096 DC to DC related charging concern or for inoperative AC charging. • The ICCU fuse accessible from a rear side panel of the EV Battery, should NEVER be replaced by itself prior to receivin
• TSB_ELE192_R1
  2023-01-18 · Electrical System
• TECHNICAL SERVICE BULLETIN: SERVICE ACTION: BMS/OPU/MCU LOGIC IMPROVEMENT (SA411) - This bulletin has been revised to include additional information. New/revised sections of this bulletin are indicated by a black bar in the margin area. This bulletin provides the procedure to improve the logic of the Battery Management System (BMS), Oil Pump Control Unit (OPU) and Motor Control Unit (MCU) on some
• TSB_ELE192
  2020-04-02 · Electrical System
• TECHNICAL SERVICE BULLETIN: SERVICE ACTION: BMS/OPU/MCU LOGIC IMPROVEMENT (SA411) - This bulletin provides the procedure to improve the logic of the Battery Management System (BMS), Oil Pump Control Unit (OPU) and Motor Control Unit (MCU) on some 2017-2019MY Optima (JF P/HEV) vehicles, produced from August 25, 2016 through September 13, 2018 (refer to page 8) in order to improve the BMS diagnosis
• 20-01-003H
  2020-01-16 · Electrical System
• 2016 - 2017 model year Sonata LF HEV vehicles contain a Power Relay Assembly. The PRA is equipped with a main relay and High Voltage Cable, which in some instances may have a loose connection. If the vehicle continues to operate in this condition, a loose connection could cause a no start condition or a Check Engine and Hybrid Warning Light On with either or both of these DTCs stored: DTC P1B77 H

A stored code names the test that failed, never the part that caused it. It is the starting point of a diagnosis, not its conclusion — the same code has several possible causes and the cheap one is not always right.