Cheeping/ticking during heating
Topic number

LI83.20-P-079911

Version

1

Function group

83.20 - Heating

Date

10/20/25

Validity

BR174

Reason for change

Complaint
High-frequency cheeping or ticking when heating is requested in the instrument panel area.

Cause
Variable switching frequencies in the high-voltage on-board electrical system can cause vibrations that lead to noise
complaints on the HV-PTC N33/16 (air heater).

Remedy
Note: Replacing the hardware does not solve the problem at present!
Modified hardware for the HV-PTC (air heater) will be available from the beginning of 2026.

Disclaimer
NOTE: The information contained in this document is intended for use by trained, professional technicians with the
knowledge to properly and safely perform diagnosis and repairs on Mercedes-Benz vehicles, using Mercedes-Benz
approved tools and equipment. It informs service technicians about conditions that could occur in certain vehicles and
provides information that could assist in proper vehicle diagnosis, service, or repair. It does not indicate that a defect
is present in any vehicle referenced in this document nor does it imply warranty coverage. DO NOT assume that a
symptom or condition, or a described cause of a symptom or condition, affects any particular vehicle or groups of vehicles, or that a described repair applies to any particular vehicle or groups of vehicles. There can be multiple causes
resulting in the same or similar symptoms or conditions described in this document, and trained professional service
technicians must use their diagnostic skills to make evaluations on a case-by-case basis. The information contained
in this document does not guarantee warranty coverage nor does it extend the vehicle’s warranty in any way.

Symptoms
Body > Air conditioning > Heater > Noise

Operation numbers/damage codes
Op. no.

Operation text

21.10.2025 15:47
© Copyright Mercedes-Benz AG

Time

CCUSHWA

Damage
code

Note

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21.10.2025 15:47
© Copyright Mercedes-Benz AG

CCUSHWA

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