What Causes the Car to Shake When the Oxygen Sensor is Plugged in but Not When Unplugged?
3 Answers
Oxygen sensor unplugged car does not shake but plugged in shake is because the oxygen sensor is damaged. In this case, it is necessary to go to a 4S shop or auto repair shop to replace the new oxygen sensor. The following are related introductions: The impact of front oxygen sensor damage on the car: Excessive exhaust emissions; deterioration of engine conditions; the vehicle stalls at idle; inaccurate engine operation and reduced power; the engine computer cannot accurately judge the mixture condition; affects the normal operation of the three-way catalytic converter. The role of the oxygen sensor: The car oxygen sensor is a key feedback sensor in the electronic fuel injection engine control system, and is a key component to control car exhaust emissions, reduce car pollution to the environment, and improve the fuel combustion quality of the car engine. The oxygen sensor is installed on the engine exhaust pipe. Maintenance of the oxygen sensor: Check the working status of the oxygen sensor every 30,000 kilometers. If it is aging or failing, clean or replace the new oxygen sensor in time.
I've seen this situation quite often in repair shops - the engine shakes when the oxygen sensor is connected, but runs smoothly when it's disconnected. There's a lot to understand here. The oxygen sensor reports data to the engine computer, which adjusts the air-fuel mixture accordingly. If the sensor signal is faulty, the computer makes incorrect adjustments, causing the mixture to become either too rich or too lean, resulting in severe shaking. Possible causes include sensor aging/contamination, poor connector contact causing unstable signals, which subsequently affects ignition and fuel injection. The most troublesome issue is wiring problems - short circuits occurring when the connector is plugged in, causing the computer to immediately report errors. I recommend first reading fault codes with a diagnostic tool, focusing on checking whether the sensor signal voltage is stable, then inspecting the wiring harness for any wear or grounding issues. 160
This is actually quite common, and I've analyzed several cases. After the oxygen sensor is connected, the engine enters closed-loop control, and the ECU relies on it to adjust the air-fuel ratio. Once the sensor malfunctions—for example, due to a short circuit in the internal heating circuit or signal drift caused by a damaged ceramic element—the ECU will issue incorrect fuel trim commands. Engine shaking is a direct result of an imbalanced air-fuel mixture. Also, don’t forget to check for exhaust leaks, as abnormal oxygen concentration at the leak point can also cause the sensor to misread. The simplest method is to use a multimeter to measure the voltage of the sensor's power and signal lines; readings below 0.1V or above 0.9V indicate a problem.
