2024 Jeep Wrangler PCM Update for MIL and DTCs

This article details Technical Service Bulletin (TSB) 18-050-24 REV. B, issued on September 5, 2024, which addresses various performance issues in the 2024 Jeep Wrangler. This bulletin focuses on a 2024 Jeep Wrangler PCM update to resolve problems indicated by a Malfunction Indicator Lamp (MIL) illumination and specific Diagnostic Trouble Codes (DTCs).

This TSB supersedes TSB 18-050-24 REV. A, dated August 1, 2024, and has also been released as Rapid Service Update (RSU) 24-109. It applies to 2024 Jeep Wrangler vehicles built on or before August 16, 2024 (MDH 0816XX) and equipped with the 3.6L V6 VVT Engine Upgrade 1 (Sales Code ERC).

Symptoms

Owners of affected 2024 Jeep Wrangler vehicles may experience a Malfunction Indicator Lamp (MIL) illumination accompanied by one or more of the following Diagnostic Trouble Codes (DTCs):

• 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

In addition to these codes, customers might report other symptoms such as the vehicle running rough. Some owners may also see a "Service Transmission" message displayed in the Instrument Panel Cluster (IPC) due to clutch slip detection when the transfer case is in neutral. During flat towing, a transfer case mis-shift might occur while the engine is running and the clutch pedal is up with the transmission in gear.

Other software enhancements included in this update address vehicle no-starts after PCM replacement, O2 heater crack improvements, and general OBD software changes.

Cause

The root cause of these issues is identified as the Powertrain Control Module (PCM) software. An update to this software is necessary to correct the conditions leading to the MIL illumination and various DTCs.

Important Warnings and Claims Information

When performing the PCM reprogramming, specific precautions must be taken. Technicians are instructed to install a battery charger to maintain voltage between 13.2 and 13.5 volts throughout the flash process. It is crucial not to allow the battery voltage to drop below 13.2 volts or climb above 13.5 volts during the flash process, as this can disrupt the update. If the flash process is interrupted or aborted for any reason, it must be restarted from the beginning.

For warranty claims, dealers must use failure code CC (Customer Concern) with this Technical Service Bulletin. The