2024 Jeep Wrangler PCM Update: MIL, DTCs, Hybrid System Faults

This Technical Service Bulletin (TSB) 18-026-25 from Stellantis provides crucial software updates for the 2024 Jeep Wrangler 4xe, specifically targeting models equipped with the 2.0L I4 DOHC DI Turbo PHEV Engine (Sales Code ECX) and 8-Spd Auto 8P75PH PHEV Transmission (Sales Code DFY). This 2024 Jeep Wrangler PCM update aims to resolve a range of performance issues, including the illumination of the Malfunction Indicator Lamp (MIL) and various Diagnostic Trouble Codes (DTCs).

The bulletin applies to vehicles built on or before October 31, 2024. It outlines a comprehensive software reprogramming procedure for the Powertrain Control Module (PCM), the Auxiliary Hybrid Control Processor (AHCP), also known as the Power Inverter Module (PIM), and potentially the Transmission Control Module (TCM). This 2024 Jeep Wrangler PCM update is essential for addressing persistent fault conditions and improving overall vehicle operation.

Symptoms You Might Experience

Owners of affected 2024 Jeep Wrangler 4xe vehicles may notice several symptoms indicating a need for this software update. The primary indicator is a Malfunction Indicator Lamp (MIL) illumination on the dashboard. Alongside the MIL, you might experience one or more of the following:

• "Service Hybrid System" message displays on the Instrument Panel Cluster (IPC).
• A 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 the transmission in neutral.

Fault Codes / DTCs

When the Malfunction Indicator Lamp (MIL) is illuminated, technicians may find one or more of these specific Diagnostic Trouble Codes (DTCs) stored in the vehicle's system:

Code	Description
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

Diagnosis and Trigger Conditions

Before performing the software update, a technician will use a Scan Tool (wiTECH) to verify that all related systems are functioning as designed. This involves following the appropriate Diagnostic Procedures available in DealerCONNECT/Service Library. If any DTCs or symptom conditions other than those listed in this bulletin are present, they should be recorded and repaired first. If the customer reports any of the symptoms detailed above, the technician will proceed with the repair procedure outlined in TSB 18-026-25.

Important Warnings for Technicians and Owners

This bulletin includes critical safety warnings that technicians must follow, and owners should be aware of:

• "Before performing the software reprogramming, it is necessary to make the vehicle safe." This involves ensuring the power supply of the high-voltage system is disconnected throughout the operation to prevent injury.
• "Only specifically trained technicians qualified to perform repairs on vehicles with high voltage systems under current national laws/regulations are authorized to work on the vehicle." High-voltage systems require specialized training and equipment.
• "The vehicle must not be connected to a high voltage charger when performing software updates." Connecting a charger during the update can interrupt the process and cause issues.
• "Install a battery charger to ensure sufficient battery voltage is provided during the flash process." Maintaining stable battery voltage is crucial for a successful software update.
• "If this flash process is interrupted/aborted, the flash should be restarted." An interrupted flash can lead to module corruption.

Repair Procedure Summary

The repair involves updating the software for several key control modules. This 2024 Jeep Wrangler PCM update will be performed by a certified technician using a wiTECH scan tool. The general steps are as follows:

1. Vehicle Preparation: The technician will first disable the High Voltage (HV) Battery Contactors using the wiTECH tool to ensure safety during the procedure.
2. PCM Reprogramming: The Powertrain Control Module (PCM) will be reprogrammed with the latest available software.
3. AHCP Reprogramming: The Auxiliary Hybrid Control Processor (AHCP), also known as the Power Inverter Module (PIM), will also receive the latest software update.
4. TCM Check and Reprogramming: The technician will check if a software update is available for the Transmission Control Module (TCM). If an update is available, the TCM will also be reprogrammed.
5. Post-Reprogramming: After all necessary modules are updated, the HV Battery Contactors will be re-enabled using wiTECH. Finally, any Diagnostic Trouble Codes (DTCs) that may have been set during the reprogramming process will be cleared from all modules.

This procedure typically takes 0.6 to 0.7 hours for the reprogramming itself, plus an additional 0.2 hours for disabling and enabling the HV battery contactors.

Required Tools

The primary tool required for this service is the wiTECH diagnostic system or an equivalent.

What Owners Should Do

If your 2024 Jeep Wrangler 4xe is exhibiting any of the symptoms described, such as a lit Malfunction Indicator Lamp (MIL), specific DTCs like P2450, or the "Service Hybrid System" message, you should schedule an appointment with an authorized Jeep dealership. This software update is reimbursable under warranty provisions. Be sure to mention the symptoms you are experiencing to the service advisor.

Superseded Bulletin

This Technical Service Bulletin (TSB) 18-026-25 supersedes TSB 18-013-24 REV. C, which was issued on June 19, 2024. The current bulletin includes an updated build date, new sales codes, additional DTCs, new customer symptoms, and revised repair procedures. If you previously searched for or were aware of TSB 18-013-24 REV. C, this new bulletin provides the most current information and solution.

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Source: NHTSA ID: 11018699