A change in running quality when air conditioning is requested needs an assessment of both the engine and the added operating demand. A rough idle does not necessarily mean the climate controller is faulty, and switching the system off is not a diagnosis.
Compare the two states
Record whether the symptom is a brief speed change, sustained shaking or an actual stall. Note engine temperature, any unusual compressor-area noise and whether the warning lamp flashes or remains on. Include recent engine or air-conditioning work.
If a warning indicates a serious misfire or the vehicle runs severely poorly, stop and seek advice. Do not bypass compressor controls to force operation. The technician should examine the relevant engine data and mechanical or electrical evidence before recommending an ECU repair. Preserve the original scan and describe whether the complaint also occurs with other loads, because that comparison can change the direction of the investigation.
Related help
- Engine Starts Then Stalls When Electrical Loads Are Switched On
- Fuel Gauge Reads Empty Immediately After Refuelling
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