Why does the Audi Q5 experience acceleration shaking and the engine fault light illuminate?
2 Answers
When the engine fault light illuminates accompanied by vehicle shaking, the cause is typically poor combustion of the air-fuel mixture. Incomplete combustion leads to carbon deposits in the engine - the primary reason for vibration. Simultaneously, when oxygen sensors detect this condition and report it to the ECU, the system triggers the warning light. This explains why engine warning lights and shaking often occur together. Multiple components can cause poor mixture combustion including faulty spark plugs, defective ignition coils, malfunctioning fuel pumps, or clogged fuel lines. When the engine warning light activates, follow these steps: First, observe whether the engine operates normally - check for vibrations, black smoke emissions, or starting difficulties. If present, avoid restarting the engine. Important note: Never restart when the red warning light appears. If the engine runs normally and the vehicle remains drivable, proceed immediately to a service center for diagnosis. Technicians can quickly retrieve trouble codes using portable diagnostic equipment to identify and address specific issues. For normally functioning engines, owners may attempt gently reseating all wiring harness connectors (in case of loose connections) or repeatedly turning the ignition to ON position to potentially reset the system.
I just experienced a similar situation. While accelerating my Audi Q5, it suddenly started shaking violently, and the engine warning light immediately came on, which really alarmed me. The cause is mostly related to ignition system issues, such as worn-out spark plugs or excessive carbon buildup, leading to misfires in one of the cylinders and uneven power output, resulting in shaking. It could also be a faulty ignition coil, especially noticeable when flooring the throttle at high speeds. Clogged fuel injectors can disrupt the air-fuel mixture ratio, increasing engine vibration and triggering the warning light. Another possibility is a faulty mass airflow sensor, causing insufficient air supply and excessive fuel, leading to vibrations. Later, during diagnostics, the scanner showed a P0300 code—a misfire issue. I recommend not ignoring such minor symptoms, as prolonged wear on parts can be troublesome. Replacing the spark plugs usually solves the problem at a low cost while improving driving safety. Regularly inspect these components and develop good maintenance habits.
