The vehicles mentioned above may experience a failure of the air-conditioning system. A defective coolant thermostat must be considered as a possible cause for such failures.
When the motor is switched off and is still warm from operation, the coolant temperature increases (to 130°C).
As a result, the thermostat opens "up to the limit stop." It can get stuck in this position. The on-board electronics system interprets this as a faulty temperature setting and switches off the air-conditioning system.
The error code P0128 (coolant thermostat) is then stored in the error memory.
In order to remedy this situation, the thermostat should be replaced and the error memory cleared.
Important safety note
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