Why is the exhaust brake indicator light on?
2 Answers
Exhaust brake indicator light on indicates that the vehicle's exhaust brake is currently working. Here are some common misconceptions about exhaust brakes: 1. Harm to the engine: Since the principle of exhaust braking is to block the exhaust manifold, causing increased pressure in the exhaust pipe which produces a distinctive sound, some people believe exhaust braking may damage the engine. In reality, the butterfly valve in the exhaust system doesn't completely seal the exhaust manifold, but rather adjusts its opening based on the pressure in the exhaust manifold, thus causing no harm to the engine. 2. Increased engine carbon deposits: Exhaust braking systems have a fuel cut-off function when activated. Using exhaust braking to stop the engine doesn't "choke" the vehicle, but rather utilizes this fuel cut-off function to shut down diesel engines. Therefore, when exhaust brake is engaged, the fuel injectors stop spraying fuel, preventing carbon buildup.
I've been driving for over a decade, and the exhaust warning light coming on is definitely not a good sign. The most common causes are a stuck or faulty exhaust brake switch, or erroneous signals from the control system, such as sensor malfunctions. Especially during long-distance driving or downhill mountain roads, when this light comes on, it means reduced auxiliary braking power, which can increase the burden on the brakes and even pose safety risks. My advice is not to panic. Pull over and check the switch position and fuse box to see if any fuses are blown. If the light remains on, don't force the drive; head to a professional repair shop immediately for diagnosis. Regular maintenance should include attention to cleaning carbon deposits from the exhaust system to prevent such issues.
