2021 Jeep Wrangler MIL Illumination TSB 08-314-25

Owners of certain 2021 Jeep Wrangler vehicles may notice a "Malfunction Indicator Lamp (MIL) illumination" on their dashboard, often accompanied by specific Diagnostic Trouble Codes (DTCs). This issue, detailed in Technical Service Bulletin (TSB) 08-314-25, revision 08-020-22, points to a software problem within the vehicle's amplifier module. This bulletin supersedes the previous Technical Service Bulletin (TSB) 08-020-22, issued on January 27, 2022.

This bulletin applies to 2021 Jeep Wrangler models equipped with the Premium Alpine Speaker System (Sales Code RC3) that were built between June 21, 2021 (MDH 0621XX) and September 06, 2021 (MDH 0906XX). The problem stems from faulty amplifier software, which causes the vehicle to incorrectly set certain DTCs without actually affecting the Active Noise Cancellation (ANC) performance. This TSB is applicable to vehicles in North and South America, Enlarged Europe, Middle East & Africa, India & Asia Pacific, and China markets.

Symptoms

If your 2021 Jeep Wrangler is affected, you will experience a "Malfunction Indicator Lamp (MIL) illumination" on your instrument cluster. This warning light indicates that the vehicle's computer has detected a fault.

Fault Codes / DTCs

When the "Malfunction Indicator Lamp (MIL) illumination" occurs, a scan tool will likely reveal one or more of the following Diagnostic Trouble Codes (DTCs):

It is important to note that these DTCs are often wrongly set and do not affect the Active Noise Cancellation (ANC) performance of your Jeep Wrangler MIL illumination.

Diagnosis

Before proceeding with the repair, a technician will use a wiTECH scan tool to verify all related systems are functioning as designed. If other DTCs or symptom conditions are present, they must be addressed first. If the customer reports the symptoms described in this bulletin, the repair procedure outlined below should be followed.

Repair Procedure Summary

The primary repair involves updating the Amplifier (AMP) module with the latest available software. This process requires specific steps to ensure proper execution and prevent further issues.

1. Check for DTCs: The technician will first check if DTC B143B-12 is stored. If it is, they will proceed to the next step. If not, they will follow standard diagnostic procedures.
2. Reprogram AMP Module: The Amplifier (AMP) module will be reprogrammed with the most current software using the wiTECH Diagnostic Application. If any issues arise during this flashing process, the technician is instructed to submit a ticket to the Helpdesk.
3. Perform EPS Reset: After the AMP software update, an Electric Power Steering (EPS) reset must be performed using the wiTECH tool. This involves navigating to the “Guided Diagnostics” menu, selecting