2024 Jeep Wrangler PCM Updates for MIL and DTCs

Owners of 2024 Jeep Wrangler vehicles equipped with a 3.6L V6 VVT Engine Upgrade 1 (Sales Code ERC) may experience a Malfunction Indicator Lamp (MIL) illumination on their dashboard. This issue is often accompanied by specific Diagnostic Trouble Codes (DTCs) and other operational concerns. This article details the symptoms, fault codes, and the necessary repair procedure outlined in TSB 18-003-26, which involves updating the Powertrain Control Module (PCM) software.

Symptoms

Owners of affected 2024 Jeep Wrangler vehicles may notice the Malfunction Indicator Lamp (MIL) illuminated on the instrument cluster. This can be accompanied by a range of specific Diagnostic Trouble Codes (DTCs) stored in the vehicle's computer system. The 2024 Jeep Wrangler PCM updates are designed to address these issues.

In addition to the MIL, customers might observe a "Service Transmission" message displayed in the Instrument Panel Cluster (IPC), particularly in manual transmission models, due to clutch slip detection. It's important to note that wheel spin or slippage might be interpreted by the PCM as excessive clutch slip, leading to this message to prevent clutch damage. Other reported symptoms include the vehicle running rough or experiencing a transfer case mis-shift during flat towing conditions (engine running, clutch pedal up, transmission in gear, manual transmission only).

Fault Codes / DTCs

The following Diagnostic Trouble Codes (DTCs) may be set in conjunction with the symptoms described for the 2024 Jeep Wrangler PCM updates:

Code	Description
P08A6	Gear Lever Position Sensor System - Multiple Sensor Correlation (Manual Transmission Only)
P0032	O2 - Sensor 1/1 Heater Circuit High
P0038	O2 - Sensor 1/2 Heater Circuit High
P0052	O2 - Sensor 2/1 Heater Circuit High
P0058	O2 - Sensor 2/2 Heater Circuit High
P1129	Closed Loop Fueling Not Achieved-Banks 2 Upstream
P0152	O2 Sensor 2/1 Circuit High
P0158	O2 Sensor 2/2 Circuit High
P2504	Charging System Output High
P0563	System Voltage High

Important Warnings

When performing the PCM reprogramming, it is critical to install a battery charger to maintain stable voltage. The battery voltage must not drop below 13.2 volts during the flash process, and the charging voltage should not exceed 13.5 volts. If the flash process is interrupted or aborted, it must be restarted.

Diagnosis

To diagnose these issues, technicians will use a wiTECH scan tool. They will verify if the vehicle's VIN is included in the Rapid Service Update (RSU) 24-109 list. If the VIN is on the list, or if the customer's symptoms match those described in TSB 18-003-26, the repair procedure should be followed. Any other DTCs or symptom conditions not listed in this bulletin should be addressed separately after confirming the primary issue.

Repair Procedure Summary

The repair for the 2024 Jeep Wrangler PCM updates primarily involves updating the Powertrain Control Module (PCM) software. The process is as follows:

1. Check VIN Eligibility: The technician first verifies if the vehicle's VIN is part of the RSU VIN list. If not, but the symptoms match, the repair proceeds.
2. Software Check: Determine if the PCM already has the latest software installed. If it does, the bulletin is considered complete using labor operation 18-19-06-KA.
3. PCM Reprogramming: If the software is not current, the PCM is reprogrammed with the latest available software using the wiTECH Diagnostic Application. Any issues during this process require contacting the Helpdesk.
4. DTC Verification: After reprogramming, the technician checks if any of the specified DTCs (P08A6, P0032, P0052, P0058, P0038) return. If they do, further diagnostics are required using published DTC repair procedures.
5. Clear DTCs: Finally, all DTCs that may have been set in any module during the reprogramming process are cleared using the wiTECH application.

This bulletin also includes other software enhancements such as improvements for vehicle no-starts after PCM replacement, O2 heater crack improvements, and general OBD software changes.

Required Tools or Parts

To perform the PCM software update, a wiTECH scan tool or an equivalent diagnostic tool is required.

Owner Action

If your 2024 Jeep Wrangler is exhibiting a Malfunction Indicator Lamp (MIL) illumination, displaying a "Service Transmission" message, or setting any of the listed DTCs, you should contact your authorized Jeep dealership. Explain the symptoms you are experiencing. The dealership will be able to verify if your vehicle is covered under TSB 18-003-26 and perform the necessary PCM software update. This repair is reimbursable under the provisions of the vehicle's warranty.

NHTSA ID: 11027850