2024 Jeep Wrangler PCM Update for Misfire & O2 Sensor DTCs

Owners of 2024 Jeep Wrangler vehicles may experience a range of engine performance issues, often accompanied by a lit Malfunction Indicator Lamp (MIL). These issues, including rough idle, engine misfires, and various O2 sensor-related fault codes, are addressed by a specific software update for the Powertrain Control Module (PCM). This update is detailed in Technical Service Bulletin (TSB) 18-003-26 REV. A.

This TSB, dated April 16, 2026, supersedes an earlier version, TSB 18-003-26, issued on January 24, 2026. It also relates to Rapid Service Update (RSU) 24-109, which was released on August 01, 2024. The bulletin applies to 2024 Jeep Wrangler models equipped with the 3.6L V6 24V VVT Engine UPG 1 W/ESS (Sales Code ERC) and is applicable across various global markets, including North America.

Symptoms

Customers may observe a Malfunction Indicator Lamp (MIL) illumination on the dashboard. Beyond the warning light, specific drivability concerns may include:

• "The vehicle has a rough idle."
• "The engine has a miss or runs rough."
• "Noisy valvetrain."
• A "Service Transmission" message in the Instrument Panel Cluster (IPC).

These symptoms are often linked to specific Diagnostic Trouble Codes (DTCs) stored in the vehicle's system.

Fault Codes / DTCs

If your 2024 Jeep Wrangler is experiencing the symptoms described, one or more of the following DTCs may be present:

Code	Description
P0300	Multiple Cylinder Misfire (Active or Stored status set during cold start catalyst heating)
P0301	Cylinder 1 Misfire (Active or Stored status set during cold start catalyst heating)
P0302	Cylinder 2 Misfire (Active or Stored status set during cold start catalyst heating)
P0303	Cylinder 3 Misfire (Active or Stored status set during cold start catalyst heating)
P0304	Cylinder 4 Misfire (Active or Stored status set during cold start catalyst heating)
P0305-00	Cylinder 5 Misfire (Active or Stored status set during cold start catalyst heating)
P0306-00	Cylinder 6 Misfire (Active or Stored status set during cold start catalyst heating)
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
P08A6	Gear Lever Position Sensor System - Multiple Sensor Correlation (Manual Transmission Only)
P152F	Engine Hood Switch 2 / Engine Hood Switch 1 Correlation

Diagnosis / Trigger Conditions

The root cause of these issues is identified as the PCM software. In some cases, the PCM may misinterpret events like wheel spin or traction loss as excessive clutch slip, leading to a "Service Transmission" message. Additionally, during flat-towing, an unintended transfer case shift can occur if the engine is running and the transmission is in gear.

The TSB also highlights several software enhancements included in the update:

• Improved engine oil pump operation, commanding high-pressure mode when cold to enhance valvetrain component durability.
• Better logic to prevent no-start conditions after PCM replacement.
• Enhanced O2 heater diagnostics and durability to reduce heater element cracking.
• General OBD software changes.

Repair Procedure Summary

The primary repair involves reprogramming the Powertrain Control Module (PCM) with the latest available software. A technician will use a wiTECH scan tool or equivalent to perform this update. After the flash, any stored DTCs will be cleared. If certain DTCs (P08A6, P0032, P0052, P0058, or P0038) return, further diagnostic steps will be followed.

Required Tools or Parts

To perform this PCM update, a wiTECH or equivalent diagnostic scan tool is required. No specific parts are listed for replacement as part of this software update.

Important Warnings

• Battery Voltage During Flash: It is crucial to install a battery charger to maintain voltage between 13.2 and 13.5 volts during the flash process. Allowing the voltage to drop below 13.2 volts or climb above 13.5 volts can interrupt the process.
• Interrupted Flash: If the flash process is interrupted or aborted, it must be restarted.
• SA Market Note: For vehicles in the SA (South America) market only, it is not necessary to send DID-I or DID-A after applying this TSB.

Owner Action

If your 2024 Jeep Wrangler is exhibiting a rough idle, misfires, or you see a Malfunction Indicator Lamp (MIL) illuminated with any of the listed DTCs, you should schedule an appointment with your authorized Jeep dealer. The PCM software update is reimbursable under warranty provisions. The labor time for this procedure is estimated at 0.2 hours under labor operation 18-19-06-N2.

NHTSA ID: 11031448