What is the reason for the high exhaust temperature warning light?
3 Answers
It is likely due to the idle switch not closing. When the idle contact is disconnected, the ECU determines that the engine is under partial load. At this time, the ECU determines the fuel injection quantity and injection time based on the signals from the air flow sensor, crankshaft position, and engine speed. The exhaust temperature warning light in modern cars is higher due to the installation of a three-way catalytic converter. Here is additional information: Car indicator lights: The engine fault indicator light is labeled as CHECK ENGINE or MIL. It has two states and indications: one is a constant light, indicating that there is a fault in the engine's electronic control system; the other is a flashing light, indicating that the fault is still affecting some performance of the engine.
I get quite nervous when this light comes on while driving. It usually indicates that the exhaust system temperature is too high, most commonly seen in diesel vehicles, such as when the particulate filter is clogged and not cleaned in time, or poor fuel mixture leads to excessive emissions. If you drive long distances frequently at low speeds, exhaust particles can easily accumulate. Also, if the oxygen sensor is faulty and provides inaccurate temperature feedback, it may trigger a false alarm. Problems with the cooling system, like insufficient coolant or a non-functioning fan, can prevent the exhaust from cooling effectively. The scariest scenario is when the actual temperature is genuinely too high, potentially causing the catalytic converter to melt and get damaged, or even leading to a fire. I recommend slowing down and pulling over when the light comes on, then heading to a professional shop as soon as possible to check the diagnostic codes.
Last time this light came on in my car, I did a round of troubleshooting myself. First, I plugged in the OBD scanner to read the error codes and confirm if it was a false alarm. Then, I checked the engine bay, especially the oxygen sensor near the exhaust manifold for any looseness or carbon buildup. I cleaned the air filter to ensure smooth airflow and avoid incomplete fuel combustion. I also popped the hood to check the coolant level, as low antifreeze can affect cooling efficiency. For diesel vehicles, pay special attention to the DPF filter status and use a diagnostic tool to initiate a stationary regeneration cycle to see if it resolves the issue. Finally, verify the condition of the spark plugs, as misfires leading to incomplete combustion could also be a potential cause. Take your time through the process, and always prioritize safety.
