2021 Jeep Wrangler PHEV Battery MIL False Illumination TSB

Owners of the 2021 Jeep Wrangler PHEV may experience a false Malfunction Indicator Lamp (MIL) illumination related to their vehicle's plug-in hybrid electric vehicle (PHEV) battery system. This issue, addressed by NHTSA Manufacturer Communication 10248015, indicates that the MIL may turn on without an actual underlying problem with the battery. The communication outlines specific diagnostic trouble codes (DTCs) that trigger this false warning and provides a software update as the solution.

This concern primarily affects the 2021 Jeep Wrangler PHEV battery MIL system, leading to unnecessary worry for vehicle owners. The root cause is often incorrect readings or communication issues within the battery management system, rather than a critical fault with the battery itself.

Symptoms

The primary symptom owners will notice is the illumination of the Malfunction Indicator Lamp (MIL) on the dashboard. This warning light indicates a potential issue with the PHEV battery system. Despite the MIL being active, the vehicle may operate normally, suggesting a false alert rather than a genuine malfunction.

Fault Codes / DTCs

Several specific diagnostic trouble codes (DTCs) have been identified as triggers for the false 2021 Jeep Wrangler PHEV battery MIL illumination. These codes point to various aspects of the battery and control systems:

• P1A21-00: HV Battery Contactor Control Sequence Incorrect
• P0B3E-00: Hybrid/EV Battery Voltage Sense 1 Circuit High
• P0607-00: ECU Internal Performance
• P1E1B-00: Hybrid/EV Battery Side Voltage System Isolation
• P0AA4-00: Hybrid Battery Negative Contactor Circuit Stuck Closed
• P1C00-00: Hybrid/EV Battery Voltage Sense 1 Out Of Range Low
• P1C01-00: Hybrid/EV Battery Voltage Sense 1 Out Of Range High
• P1A9B-00: Hybrid/EV Battery Temperature Sensor 1 Out Of Range High
• P0BBD-00: Hybrid Battery Pack Voltage Variation Exceeded Limit
• P167B-00: Controlled System Shutdown
• U1885-00: Battery Energy Control Module Lost Communication With HCP
• P0EDD-00: Hybrid/EV Battery Pack B Deterioration
• U0111: Lost Communication With Hybrid Battery Pack Sensor Module
• P0CA7-00: Hybrid/EV Battery Discharging Current High
• P1A0C-00: Battery Energy Control Module System Voltage Low

Repair Procedure Summary

The resolution for the false 2021 Jeep Wrangler PHEV battery MIL involves updating the software of several key control modules. This is a flash update designed to correct the diagnostic logic and communication protocols that lead to the erroneous MIL illumination. The primary module targeted is the Battery Pack Control Module (BPCM).

However, for the update to be fully effective, additional modules also require software updates. These include the Powertrain Control Module (PCM), Integrated Dual Charging Module (IDCM), Transmission Control Module (TCM), and the Hybrid Control Processor (HCP), which is also known as the Auxiliary Hybrid Control Processor (AHCP) or Power Inverter Module (PIM).

Owner Action

If you own a 2021 Jeep Wrangler PHEV and are experiencing a false Malfunction Indicator Lamp (MIL) illumination, especially if accompanied by any of the listed DTCs, you should contact your authorized Jeep dealership. The dealership will be able to perform the necessary software updates for the Battery Pack Control Module (BPCM) and other related modules. This software flash is expected to resolve the issue and prevent the MIL from falsely illuminating in the future.

Source: NHTSA ID: 10248015