2012-2026 Stellantis Transmission Warning TSB S2621000003

Stellantis has released Technical Service Bulletin (TSB) S2621000003 REV. A, dated March 2026, to address concerns regarding the "service transmission/check engine warning indicator" in various 2012-2026 Chrysler, Dodge, Jeep, Ram, and Alfa Romeo vehicles. This bulletin provides diagnostic guidance and repair procedures for specific 8-speed transmission models that may exhibit certain diagnostic trouble codes (DTCs). This information is crucial for owners of affected vehicles, including the 2024 Alfa Romeo Stelvio manufacturer_communication, to understand potential issues and the recommended course of action.

Symptoms and Affected Transmissions

Owners of affected vehicles may observe a "service transmission/check engine warning indicator" illuminating on their dashboard. This issue is specific to vehicles equipped with the following 8-speed transmission models:

• 845RE
• 8HP45
• 850RE
• 8HP50
• 8HP70
• 8HP75
• 8HP75-PHEV
• 8HP75-LCV
• 8HP90
• 8HP95

Diagnostic Trouble Codes (DTCs)

Transmissions exhibiting the described symptoms may also log one or more of the following diagnostic trouble codes (DTCs):

• P07E4
• P1DB2
• P0716
• P1B14
• P0733
• P1D90
• P1DB7
• P1B13

Important Diagnostic Considerations and Warnings

Stellantis TSB S2621000003 REV. A provides crucial warnings regarding transmission diagnosis:

• Fluid Smell: 8-speed transmission fluid normally has a burnt odor characteristic due to its oil additives. This fluid smell is explicitly stated as not a symptom to authorize a transmission replacement.
• Visual Inspection: Visual inspection of the fluid in the oil pan is a subjective process and does not typically indicate a gearbox issue. Normal wear from customer driving can create fine metallic debris, which should only be considered an indicator of internal transmission damage or replacement in extreme cases.
• Warranty: This document does not authorize warranty repairs. It serves as a record of past experiences and does not provide conclusions about vehicle issues. Technicians are responsible for determining the appropriate course of action.

Repair Procedure Summary

If the listed DTCs are active or stored, the following repair procedure should be followed:

1. MPR Cable Check: For DTCs P1B13 and P1B14, ensure the MPR cable is not slightly applied or stuck.
2. Clutch D Repair (for P0733): For diagnostic code P0733, technicians must first follow TSB 21-009-25 Rev C (for 850RE transmissions) or TSB 21-029-25 REV. A (for 8HP75 transmissions) for the proper clutch D repair. If issues persist after this repair, a valve body replacement should be considered.
3. Valve Body Replacement: This is the primary recommended repair option before considering a full transmission replacement. A complete transmission replacement should only be considered if serious and obvious gearbox damage exists prior to any repairs.
4. Post-Repair Diagnostics: If any concerns persist after the valve body replacement, technicians must record all new codes from a fresh Scan Report and perform further diagnostics related to both new codes and shift quality concerns.

Required Documentation for Diagnosis

To properly diagnose and address these transmission issues, specific documentation and evidence are required:

• Transmission Diagnostic Worksheet: This worksheet must be fully completed.
• Transmission Shift Quality Worksheet: For cases involving shift quality concerns, this worksheet must also be fully completed.
• Visual Evidence: Clear and concise pictures showing any damage, pan debris, and fluid condition should be attached when submitting a STAR ticket or request to PTSC (Product Technical Support Center).

Owner Action

If your vehicle, including a 2024 Alfa Romeo Stelvio manufacturer_communication, displays a "service transmission/check engine warning indicator" or exhibits symptoms related to the affected transmissions and DTCs, it is crucial to visit an authorized Stellantis dealer. They have access to the full technical bulletin and the necessary diagnostic tools and procedures to accurately diagnose and repair the issue. Ensure all required diagnostic worksheets are completed by the technician and any visual evidence is documented.

NHTSA Source: S2621000003 REV. A