B12B4 on the 2024 Jeep Wrangler
The bulletins listed name this code in NHTSA's summary, or are about the same components. A bulletin or a recall listed here may apply to the model year. None of it is a diagnosis.
This code is specific to a manufacturer and is not described here. Its meaning is in the manufacturer's service information.
| 18-026-25 REV. A | 2025-07-31. Service bulletin. Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle mustexhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● **P04B5 - Fuel Fill Door Stuck Open. ● P1D83 - Implausible Engine Oil Temperature Signal Received.** ● P2450 - Fuel Tank Isolation Valve Stuck Open. ● P0032 - O2 Sensor 1/1 Heater Circuit High. ● P2097 - Downstream Fuel Trim System 1 Rich. ● P0171 - Fuel System 1/1 Lean. ● P0300 - Multiple Cylinder Misfire. ● P06E4 - Control Module Wake-Up Circuit Performance. ● B12B4 - Charge Status Indicator Module Internal. ● P061B - Internal Control Module Torque Calculation Performance. ● P0810 - Clutch Position Control Error. ● P2885 - Engine Disconnect Clutch Engagement Fault. Customers may also experience one or more of the following: ● **Decreased Fuel Efficiency. ● Reduced engine performance or rough idling.** ● "Service Hybrid System" message displays on the Instrument Panel Cluster (IPC). ● Wrench icon displays on the IPC. ● Vehicle misfires. ● Low speed engine stall at idle. ● Difficulty shifting out of 4LO. ● Idle creep while in 4LO with transmission in neutral. This bulletin involves reprogramming the Powertrain Control (PCM) and the Auxiliary Hybrid Control Processor (AHCP) also known as Power Inverter Module (PIM) and possibly the Transmission Control Module (TCM) with the latest available software. |
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| 18-026-25 | 2025-05-30. Service bulletin. "Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● **P2450 - Fuel Tank Isolation Valve Stuck Open.** ● P0032 - O2 Sensor 1/1 Heater Circuit High. ● P2097 - Downstream Fuel Trim System 1 Rich. ● P0171 - Fuel System 1/1 Lean. ● P0300 - Multiple Cylinder Misfire. ● P06E4 - Control Module Wake-Up Circuit Performance. ● B12B4 - Charge Status Indicator Module Internal. ● P061B - Internal Control Module Torque Calculation Performance. ● P0810 - Clutch Position Control Error. ● P2885 - Engine Disconnect Clutch Engagement Fault. Customers may also experience one or more of the following: ● **""Service Hybrid System"" message displays on the Instrument Panel Cluster (IPC). ● Wrench icon displays on the IPC.** ● Vehicle misfires. ● Low speed engine stall at idle. ● Difficulty shifting out of 4LO. ● Idle creep while in 4LO with transmission in neutral. **This bulletin involves reprogramming the Powertrain Control (PCM) and the Auxiliary Hybrid Control Processor (AHCP) also known as Power Inverter Module (PIM) and possibly the Transmission Control Module (TCM) with the latest available software.**" |
| 21-004-25 | 2025-01-14. Service bulletin. "Flash: Transmission Control Module (TCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P06E4 - Control Module Wake-up Circuit Performance. ● B12B4 - Charge Status Indicator Module Internal. ● P061B - Internal Control Module Torque Calculation Performance. ● P0810 - Clutch Position Control Error. ● P2885 - Engine Disconnect Clutch Engagement Fault. Customers may experience one or more of the following: ● Vehicle loses propulsion capability. ● 'Shift To Park' notification on. ● 'Service Transmission' warning light on. ● Requires key cycle to recover. ● Shifts rough occasionally. ● Harsh shifts when tipping in during a coast down. ● Shifts roughly during coast down. This bulletin involves reprogramming the Transmission Control Module (TCM), Powertrain Control (PCM) and the Auxiliary Hybrid Control Processor (AHCP) also known as Power Inverter Module (PIM) or reprogramming the TCM and PCM only with the latest available software" |
| 21-017-24 REV. D | 2024-06-25. Service bulletin. "Flash: Transmission Control Module (TCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P06E4 - Control Module Wake-up Circuit Performance. ● B12B4 - Charge Status Indicator Module Internal. ● P061B - Internal Control Module Torque Calculation Performance. ● P0810 - Clutch Position Control Error. ● P2885 - Engine Disconnect Clutch Engagement Fault. Customers may experience one or more of the following: ● Vehicle loses propulsion capability. ● 'Shift To Park' notification on. ● 'Service Transmission' warning light on. ● Requires key cycle to recover. ● Shifts rough occasionally. ● Harsh shifts when tipping in during a coast down. ● Shifts roughly during coast down. This bulletin involves reprogramming the Transmission Control Module (TCM), Powertrain Control (PCM) and the Auxiliary Hybrid Control Processor (AHCP) also known as Power Inverter Module (PIM) **or reprogramming the TCM and PCM only** with the latest available software." |
| 18-013-24 REV. C | 2024-06-25. Service bulletin. "Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P0032 - O2 Sensor 1/1 Heater Circuit High. ● P2097 - Downstream Fuel Trim System 1 Rich. ● P0171 - Fuel System 1/1 Lean. ● P0300 - Multiple Cylinder Misfire. ● P06E4 - Control Module Wake-Up Circuit Performance. ● B12B4 - Charge Status Indicator Module Internal. ● P061B - Internal Control Module Torque Calculation Performance. ● P0810 - Clutch Position Control Error. ● P2885 - Engine Disconnect Clutch Engagement Fault. Customers may also experience one or more of the following: ● Vehicle misfires. ● Low speed engine stall at idle. ● Difficulty shifting out of 4LO. ● Idle creep while in 4LO with transmission in neutral. This bulletin involves reprogramming the Transmission Control Module (TCM), Powertrain Control (PCM) and the Auxiliary Hybrid Control Processor (AHCP) also known as Power Inverter Module (PIM) **or reprogramming the TCM and PCM only** with the latest available software." |
| 21-017-24 REV. C | 2024-06-12. Service bulletin. "Flash: Transmission Control Module (TCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P06E4 - Control Module Wake-up Circuit Performance. ● B12B4 - Charge Status Indicator Module Internal. ● P061B - Internal Control Module Torque Calculation Performance. ● P0810 - Clutch Position Control Error. ● P2885 - Engine Disconnect Clutch Engagement Fault. Customers may experience one or more of the following: ● **Vehicle loses propulsion capability. ● 'Shift To Park' notification on. ● 'Service Transmission' warning light on. ● Requires key cycle to recover.** ● Shifts rough occasionally. ● Harsh shifts when tipping in during a coast down. ● Shifts roughly during coast down. This bulletin involves reprogramming the TCM, Powertrain Control (PCM) and the Auxiliary Hybrid Control Processor (AHCP) also known as Power Inverter Module (PIM), with the latest available software." |
| 18-013-24 REV. B | 2024-06-12. Service bulletin. "Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● **P0032 - O2 Sensor 1/1 Heater Circuit High. ● P2097 - Downstream Fuel Trim System 1 Rich. ● P0171 - Fuel System 1/1 Lean. ● P0300 - Multiple Cylinder Misfire.** ● P06E4 - Control Module Wake-Up Circuit Performance. ● B12B4 - Charge Status Indicator Module Internal. ● P061B - Internal Control Module Torque Calculation Performance. ● P0810 - Clutch Position Control Error. ● P2885 - Engine Disconnect Clutch Engagement Fault. Customers may also experience one or more of the following: ● **Vehicle misfires. ● Low speed engine stall at idle.** ● Difficulty shifting out of 4LO. ● Idle creep while in 4LO with transmission in neutral. This bulletin involves reprogramming the PCM, Transmission Control Module (TCM) and the Auxiliary Hybrid Control Processor (AHCP) also known as Power Inverter Module (PIM), with the latest available software." |
| 08-051-24 REV. B | 2024-06-12. Service bulletin. "Flash: Hybrid Control Processor (HCP) and Auxiliary Hybrid Control Processor (AHCP) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P06E4 - Control Module Wake-up Circuit Performance. ● B12B4 - Charge Status Indicator Module Internal. ● P061B - Internal Control Module Torque Calculation Performance. ● P0810 - Clutch Position Control Error. ● P2885 - Engine Disconnect Clutch Engagement Fault. Customers may also experience the following: ● Transmission torque calculation issues. This bulletin involves reprogramming the Powertrain Control Module (PCM), Transmission Control Module (TCM) and the AHCP also known as Power Inverter Module (PIM), with the latest available software." |
| 21-017-24 REV. B | 2024-06-07. Service bulletin. "Flash: Transmission Control Module (TCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P06E4 - Control Module Wake-up Circuit Performance. ● B12B4 - Charge Status Indicator Module Internal. ● P061B - Internal Control Module Torque Calculation Performance. ● P0810 - Clutch Position Control Error. ● P2885 - Engine Disconnect Clutch Engagement Fault. **Customers may experience one or more of the following: ● Shifts rough occasionally. ● Harsh shifts when tipping in during a coast down. ● Shifts roughly during coast down.** This bulletin involves reprogramming the TCM, Powertrain Control (PCM) and the Auxiliary Hybrid Control Processor (AHCP) also known as Power Inverter Module (PIM), with the latest available software." |
| 18-013-24 REV. A | 2024-06-07. Service bulletin. "Flash: Powertrain Control Module (PCM) Updates **Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs):** ● P06E4 - Control Module Wake-up Circuit Performance. ● B12B4 - Charge Status Indicator Module Internal. ● P061B - Internal Control Module Torque Calculation Performance. ● P0810 - Clutch Position Control Error. ● P2885 - Engine Disconnect Clutch Engagement Fault. **Customers may also experience one or more of the following: ● Difficulty shifting out of 4LO. ● Idle creep while in 4LO with transmission in neutral.** This bulletin involves reprogramming the PCM, Transmission Control Module (TCM) and the Auxiliary Hybrid Control Processor (AHCP) also known as Power Inverter Module (PIM), with the latest available software." |
12 on file from NHTSA, as of 2026-10-19. See them in the bulletin list. A bulletin lists model years: read the document for which vehicles it concerns.