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January 7, 2026 Service bulletin

Complaint Customer states the AC either does not cool/has poor performance or heat is insufficient

Mercedes-Benz technical service bulletin LI83.30-P-079850 for 2015-2026 Mercedes-Benz C300, 2020-2023 Mercedes-Benz E350 and 2020-2026 Mercedes-Benz GLC 300 and others.

Bulletin number
LI83.30-P-079850
Component
Visibility/wiper
Summary
Complaint Customer states the AC either does not cool/has poor performance or heat is insufficient. Cause Many possible root causes Remedy AC Diagnosis (General) Initial Steps Verify Customer Concern • Confirm the issue reported by the customer. Compare to Like Vehicle • Determine if the behavior is normal by comparing with a similar vehicle. Determine Your Game and Players • Identify the diagnostic strategy and involved components/systems. Testing • Perform relevant diagnostic tests. Refrigerant Quantity • Record the amount of refrigerant recovered and compare it to the specified value (if applicable). • Forming Gas is the ONLY approved leak test method. (DYE is NOT approved) TIPS Case Submission Requirements Cooling Capacity Test (If System Has a Charge) Before Repairs Gauge Readings • High and Low pressure readings (from machine or separate gauges). Leak Detection (if applicable) • PPM of any leaks found. XENTRY Printouts • Climate control AVs. • HV compressor AVs (for heat and AC systems). Thermometer Readings • Left and right dash vents. • Center vent, footwell, and/or rear vents (if concern is localized). Ambient Conditions • Temperature and humidity from OCP AVs (if available). After Repairs - Warranty Submission Requirements on the Repair Order Gauge Readings • High and Low pressure readings before and after repairs. Thermometer Readings • Left and right dash vents before and after. • Center vent, footwell, and/or rear vents before and after (if localized concern). Documentation • Complaint Analysis, Game/Players, and Testing Steps. • Include expected results and technical justification for the diagnosis. • Avoid listing R/I steps—focus on diagnostic reasoning and root cause. • All prior measurements need to be documented on the repair order. OP code usage: 831232 - Max .5 for Cooling Capacity Test 831040 - Only to be utilized if you have a fault code and are actively diagnosing that fault code 831762 - This includes basic leak check 831285 - This can only be used in extenuating circumstances where a leak cannot be found

Owners of these vehicles have filed 193 complaints in the visibility category.

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