Imagine you are driving a heavy truck on a steep downhill road. You need to slow down but don’t want to use your service brakes too much, as they can overheat and fail. You rely on your exhaust brake, a device that uses the engine’s compression to reduce the speed and power of the vehicle. But what if your exhaust brake not working? How would you handle the situation? What are the possible causes and solutions for this problem?
Read on to discover the common causes of the 5.9 Cummins exhaust brake not working. We will also provide tips on checking, repairing, or replacing these components to help you restore your exhaust brake function and enjoy a smooth and safe ride.
How 5.9 Cummin Exhaust Brake Work
An exhaust brake uses the engine’s compression to slow down the vehicle, reducing the wear and tear on the brakes and increasing safety and fuel efficiency. It works by restricting the flow of exhaust gases from the engine, creating a back pressure that reduces the engine speed and power.
It is usually installed on diesel vehicles, especially trucks, that carry heavy loads or travel on steep downhill roads. The device helps the driver control the vehicle’s speed without using the service brakes, which can overheat and lose effectiveness. An exhaust brake can also prolong the lifespan of the service brakes by reducing their usage.
You can operate the exhaust brake using a switch or a pedal, depending on the type and model of the device. Some exhaust brakes have different levels of pressure control, which can adjust the braking performance according to the engine speed and load. Some exhaust brakes also have an electronic system that modulates the back pressure and prevents damage to the engine or turbocharger.
The exhaust brake differs from an engine brake, another device that slows down a vehicle using the engine’s compression. An engine brake opens the exhaust valves at a specific time during the compression stroke, releasing the compressed air into the exhaust system. This creates a negative torque that slows down the engine and the vehicle. However, an engine brake can be very loud and may not be allowed in some areas.
Symptoms of a Faulty Exhaust Brake
- Reduced braking performance or control
- Increased engine noise or vibration
- Check the engine light or exhaust brake warning light on
- Smoke or smell from the exhaust system
- Damage or corrosion on the exhaust brake components
Common Causes of 5.9 Cummins Exhaust Brake Not Working
A blown fuse
A fuse protects the electrical circuit of the exhaust brake from overloading or short-circuiting. It does this by having a thin metal strip or wire that melts or breaks when the current exceeds a certain level. This stops the flow of electricity and prevents damage to the circuit or the device. A fuse can blow for various reasons, such as a faulty appliance, a power surge, a loose connection, or a worn-out wire.
When a fuse blows, it stops the power from reaching the exhaust brake, which causes it to stop working.
To fix this problem, locate and check the fuse, which controls the exhaust brake, and replace it if needed. You can find the fuse box under the hood or the dash of your truck. Use a multimeter or a test light to check if the fuse is blown. You can also look for any signs of damage, such as a broken or melted metal strip, discolored glass, or a popped-out button. If the fuse is blown, replace it with a new one of the same type and rating. You can find the rating on the end cap or the metal strip of the fuse. It is usually expressed in amps (A) or milliamps (mA). For example, a 10A fuse can handle up to 10 amps of current.
A faulty VGT actuator
A VGT actuator controls the position of the turbo vanes and how it affects the exhaust brake function. It does this by receiving signals from the engine computer and adjusting the angle of the vanes accordingly. The vanes are small blades that rotate around the turbine wheel of the turbocharger. They can change the speed and direction of the exhaust gases that enter and exit the turbocharger. This affects the amount of boost and back pressure that the turbocharger produces.
The VGT actuator can fail for various reasons, such as wear and tear, corrosion, water intrusion, or electrical issues. When it fails, it causes the turbo vanes to get stuck in one position or move erratically. This affects the performance and function of the exhaust brake.
To fix this problem, you need to test and replace the VGT actuator if required. You can use a multimeter or a scan tool for testing.
A stuck turbo
A turbo increases the power and efficiency of the engine by compressing the air that enters the combustion chamber. It uses exhaust gases to rotate a turbine wheel that drives a compressor wheel. The compressor wheel further forces more air into the intake manifold, creating more boost and power. A turbo can get stuck due to carbon buildup or wear and tear, preventing the turbine or compressor wheel from spinning freely. This affects the performance and function of the exhaust brake and the engine.
To fix this problem, inspect and clean or replace the turbo if needed. You can use a scan tool or a boost gauge to check if the turbo works correctly. You can also look for any signs of damage or corrosion on the turbo, such as cracks, leaks, or oil residue. If the turbo is stuck, you may need to remove it from the engine and clean it with a wire brush, a solvent, or a turbo cleaner kit. You may also need to replace the turbo if it is beyond repair.
A wiring problem
A wiring problem affects the electrical connections or circuits of the exhaust brake components. It can result from loose, damaged, or corroded wires, connectors, or terminals. A wiring problem can cause a loss of communication or power between the exhaust brake components, such as the switch, the actuator, the solenoid, or the sensor. This affects the performance and function of the exhaust brake.
You must check, repair, or replace the wiring to fix this. Use a multimeter or a test light to check for continuity and voltage in the wiring. You can also look for any signs of damage or corrosion on the wiring, such as cuts, burns, or rust. If there is a wiring problem, you may need to repair it with soldering, crimping, or splicing tools. You may also need to replace the wiring if it is beyond repair.
Consequences of Faulty 5.9 Cummins Exhaust Brakes
A faulty exhaust brake can have several negative consequences for your vehicle and safety. Below are some possible consequences.
- Reduced braking performance or control
It affects your ability to slow down or stop your vehicle, especially on steep downhill roads or when carrying heavy loads. This increases the risk of accidents, collisions, and wear and tear on your service brakes.
- Increased engine noise or vibration
Faulty exhaust brakes cause your engine to produce more noise or vibration, which can be annoying and distracting for you and other drivers. It can also indicate a severe problem with your turbocharger or exhaust system.
- Check the engine light or exhaust brake warning light on
It can trigger the check engine light or the exhaust brake warning light on your dashboard, which means there is a problem with your vehicle’s emissions or performance. This can affect fuel efficiency, engine power, and emissions testing.
- Smoke or smell from the exhaust system
It can cause smoke or smell from the exhaust system, which harms your health and the environment. It can also indicate a leak or a blockage in the exhaust system, damaging your engine or turbocharger.
- Damage or corrosion on the exhaust brake components
This leads to wear or corrosion on the exhaust brake components, such as the valve, the actuator, the solenoid, or the sensor. This can affect these components’ function and lifespan and may require costly repairs or replacements.
Steps to Fix Your Faulty Exhaust Brake
- Identify the cause of the problem by using a scan tool or a multimeter to check for any error codes or electrical issues.
- Locate and inspect the exhaust brake components for any signs of damage or corrosion, such as cracks, leaks, or oil residue.
- Remove and replace any faulty or damaged parts with new ones of the same type and rating. You can use a wrench, a socket, or a screwdriver to loosen and tighten the bolts and nuts.
- Test your exhaust brake by driving your vehicle on a flat road and activating the switch or pedal. You should hear a hissing sound and feel resistance when you release the throttle.
If your exhaust brake still does not work or works poorly, you may need to adjust the pressure or alignment of the valve, actuator, solenoid, or sensor. You can use a gauge or a ruler to measure and adjust the distance or angle of these components.
If your exhaust brake works well, you have successfully fixed your faulty exhaust brake.
Verdict
Are your 5.9mm cumin exhaust brakes not working? You need a functioning exhaust brake because it can help you control the speed of your vehicle without using the service brakes, which can overheat and lose effectiveness. This is especially important when driving a heavy truck or towing a trailer on steep downhill roads. An exhaust brake can also prolong the lifespan of your service brakes by reducing their usage.
However, sometimes the exhaust brake may not work correctly, causing a loss of braking performance and control. It is frustrating and a potentially dangerous problem for any truck driver.
This piece taught you the common causes of 5.9 Cummins exhaust brake not working, such as a blown fuse, faulty VGT actuator, stuck turbo, or wiring problem. We have also provided some tips on how to check, repair, or replace these components if needed. Follow the steps to restore your exhaust brake function and enjoy a smooth and safe ride.
