2023 Jeep Wrangler Misfire DTCs PCM Software Update

Owners of 2023 Jeep Wrangler vehicles equipped with the 3.6L V6 24V VVT ETORQUE Engine UPG I (Sales Code ERG) may encounter a Malfunction Indicator Lamp (MIL) illumination on their dashboard. This is often accompanied by specific Diagnostic Trouble Codes (DTCs) related to cylinder misfires. This issue, detailed in Technical Service Bulletin (TSB) 18-048-26, is attributed to the Powertrain Control Module (PCM) software and can be corrected with a software update.

This bulletin applies to vehicles sold in North and South America, India & Asia Pacific, and China markets.

Symptoms

Owners of affected 2023 Jeep Wrangler vehicles will typically observe a "Malfunction Indicator Lamp (MIL) illumination" on their instrument cluster. Alongside this warning light, the vehicle may exhibit one or more of the following Diagnostic Trouble Codes (DTCs):

• "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)."

Beyond these technical indicators, drivers might also notice the following operational issues:

• "The vehicle has a rough idle."
• "The engine has a miss."
• "Noisy valvetrain."

Fault Codes / DTCs

The following Diagnostic Trouble Codes (DTCs) are specifically linked to this PCM software issue:

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)

Diagnosis

When a 2023 Jeep Wrangler presents with these symptoms or DTCs, technicians are instructed to use a Scan Tool (wiTECH) and follow the appropriate Diagnostic Procedures available in DealerCONNECT/Service Library. It is crucial to verify that all related systems are functioning correctly. If any other DTCs or symptom conditions are present beyond those listed in TSB 18-048-26, they must be addressed and repaired before proceeding with the bulletin's specific repair.

Repair Procedure Summary

The resolution for the 2023 Jeep Wrangler misfire DTCs involves updating the Powertrain Control Module (PCM) software. The repair process is straightforward and typically takes about 0.3 hours of labor. Here's a summary of the steps:

1. Prepare the Vehicle: A battery charger must be connected to the vehicle. It is critical to maintain the battery voltage between 13.2 and 13.5 volts throughout the flash process to prevent interruptions.
2. Reprogram PCM: The PCM is reprogrammed using the wiTECH Diagnostic Application with the latest available software. If any issues arise during this step, technicians are advised to submit a ticket to the Helpdesk.
3. Clear DTCs: After the software update, all Diagnostic Trouble Codes (DTCs) that may have been set in any module due to the reprogramming must be cleared. The wiTECH application will automatically facilitate this.

Required Tools or Parts

To perform this repair, technicians will need a Scan Tool, specifically the wiTECH or an equivalent diagnostic system, which is used to access and reprogram the PCM.

Important Warnings

Owners should be aware of specific conditions during the repair process:

• "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."
• "If this flash process is interrupted/aborted, the flash should be restarted."

Owner Action

If your 2023 Jeep Wrangler is exhibiting a Malfunction Indicator Lamp, rough idle, engine miss, noisy valvetrain, or has stored misfire DTCs, it is recommended to schedule an appointment with an authorized Jeep service center. The PCM software update is reimbursable under warranty provisions.

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Source: NHTSA ID: 11031453