2023 Jeep Wrangler PCM Updates for MIL and DTCs

Jeep has issued Technical Service Bulletin (TSB) 18-090-25 to address various performance issues in certain 2023 Jeep Wrangler vehicles. This bulletin specifically targets models equipped with the 3.6L V6 VVT Engine Upgrade 1 (Sales Code ERC) and a 6-Speed Manual Transmission (Sales Code DEM) sold in North America.

The TSB outlines a solution involving a software update for the Powertrain Control Module (PCM) to resolve issues that can lead to the Malfunction Indicator Lamp (MIL) illuminating and other drivability concerns. This update aims to improve overall vehicle performance and address specific diagnostic trouble codes.

Symptoms

Owners of affected 2023 Jeep Wrangler vehicles may notice a Malfunction Indicator Lamp (MIL) illumination on their dashboard. In addition to the MIL, customers might experience one or more of the following symptoms:

• A "Service Transmission message on in the Instrument Panel Cluster (IPC) due to clutch slip detection with the transfer case in neutral."
• The clutch overheating.
• The clutch slipping on engagement.
• An inability to accelerate uphill.
• The vehicle failing to start.
• The vehicle becoming stuck in limp-home mode.

Fault Codes / DTCs

When the Malfunction Indicator Lamp (MIL) illuminates, technicians may find specific Diagnostic Trouble Codes (DTCs) stored in the vehicle's system. TSB 18-090-25 identifies the following codes:

Code	Description
P08A6	Gear Lever Position Sensor System - Multiple Sensor Correlation
P152F	Engine Hood Switch 2 / Engine Hood Switch 1 Correlation

These DTCs indicate issues with the gear lever position sensor system and the engine hood switch correlation, which are addressed by the PCM software update.

Diagnosis

To diagnose these issues, a technician will use a Scan Tool, such as wiTECH, along with the appropriate Diagnostic Procedures available in the DealerCONNECT/Service Library. They will verify that all related systems are functioning correctly. If any DTCs or symptom conditions beyond those listed in TSB 18-090-25 are present, those issues must be recorded and repaired before proceeding with the bulletin's repair procedure.

Repair Procedure Summary

The primary repair for the symptoms and DTCs described in TSB 18-090-25 is to reprogram the Powertrain Control Module (PCM) with the latest available software. This process is straightforward but requires specific precautions.

First, a battery charger must be connected to the vehicle to ensure the battery voltage remains between 13.2 and 13.5 volts throughout the flash process. After the PCM has been successfully reprogrammed, all Diagnostic Trouble Codes (DTCs) that may have been set in any module due to the reprogramming process must be cleared using the wiTECH application.

Important Warnings

When performing the PCM software update for the 2023 Jeep Wrangler PCM updates, technicians must adhere to specific guidelines:

• Battery Voltage: "Install a battery charger to ensure battery voltage does not drop below 13.2 volts. Do not allow the charging voltage to climb above 13.5 volts during the flash process."
• Interrupted Flash: "If this flash process is Interrupted/aborted, the flash should be restarted."

Required Tools or Parts

The only special tool required for this repair is the wiTECH diagnostic application or an equivalent scan tool capable of performing module reprogramming.

Owner Action

If your 2023 Jeep Wrangler is exhibiting any of the symptoms mentioned, such as a Malfunction Indicator Lamp (MIL) illumination, or if you suspect it may have DTCs P08A6 or P152F, you should schedule an appointment with an authorized Jeep dealership. The repair, which involves reprogramming the PCM, is reimbursable within the provisions of your vehicle's warranty.

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Source: NHTSA ID: 11024062