What Causes the Engine Warning Light to Illuminate When the Air Conditioner is On?

[StCooper]

When the engine warning light comes on with the air conditioner running, there could be several potential causes: 1. Poor fuel quality: This leads to incomplete combustion of the air-fuel mixture during engine operation, triggering the warning light. While it doesn't affect driving safety, it can harm the engine. 2. Damaged or loose oxygen sensor connector: A faulty oxygen sensor or loose connector can cause the mixture to become too lean or rich, resulting in the warning light activation. 3. Poor engine maintenance: Issues like worn spark plugs, faulty ignition coils, fuel pump problems, or clogged fuel lines can lead to improper combustion. 4. Dirty air filter: Since engine combustion requires proper air intake, a clogged air filter that hasn't been regularly cleaned can restrict airflow and eventually cause the engine warning light to illuminate if left unaddressed.