DAF Exhaust Brake Problems (Troubleshooting + Solutions)

daf exhaust brake problems

If you’re experiencing issues with the exhaust brake on your DAF truck, you’re not alone. Many truck owners have encountered problems with the exhaust brake not functioning as expected.

In this comprehensive guide, we will delve into the common causes of DAF exhaust brake problems and provide troubleshooting tips and solutions to help you get your exhaust brake back in working order.

Understanding the Exhaust Brake System

Before we dive into troubleshooting, let’s briefly understand how the exhaust brake system works. The exhaust brake is designed to provide additional stopping power by restricting the flow of exhaust gases through the engine.

This restriction creates backpressure, which helps slow down the truck. The exhaust brake is typically controlled by a lever on the steering column or a switch on the dashboard.

Common Symptoms of Exhaust Brake Issues

Before we start troubleshooting, it’s important to identify the common symptoms of exhaust brake problems. Here are some signs that indicate your DAF truck’s exhaust brake may not be functioning properly:

  1. The exhaust brake fails to engage when the lever or switch is activated.
  2. The exhaust brake remains engaged even when the lever or switch is in the off position.
  3. The exhaust brake produces no sound or minimal braking effect.
  4. The exhaust brake only activates when the brake pedal is pressed.

Read also >> Exhaust Brake Problems (Here Is How To Fix)

Read also >> Exhaust Gas Sensor Problems (Helpful Guide)

Troubleshooting DAF Exhaust Brake Problems

Now that we have a basic understanding of the exhaust brake system and common symptoms, let’s move on to troubleshooting the issues you may be facing with your DAF truck’s exhaust brake.

Step 1: Check the Fuse

One of the first things to check when the exhaust brake is not working is the fuse. Locate the fuse box in your truck and inspect the exhaust brake fuse.

If the fuse is blown, replace it with a new one of the same rating. Start the engine and test the exhaust brake to see if it is functioning properly.

Step 2: Inspect the Switch or Lever

If the fuse is not the issue, the next step is to inspect the switch or lever that controls the exhaust brake. Ensure that the switch or lever is in the correct position and is not damaged or faulty.

If necessary, replace the switch or lever with a new one.

Step 3: Check for Vacuum Leaks

Inspect the vacuum lines connected to the exhaust brake system. Look for any signs of damage, cracks, or leaks.

A vacuum leak can prevent the exhaust brake from functioning properly. If you find any issues with the vacuum lines, replace them to restore proper operation.

Step 4: Examine the Solenoid

The solenoid plays a crucial role in activating the exhaust brake. Locate the solenoid, which is usually located near the exhaust brake system.

Check for any signs of damage or malfunction. If the solenoid is faulty, it may need to be replaced to resolve the issue.

Step 5: Verify the Throttle Position Sensor

The throttle position sensor (TPS) is responsible for transmitting signals to engage or disengage the exhaust brake.

Ensure that the TPS is functioning correctly by testing it with a multimeter or consulting a professional mechanic. If the TPS is faulty, it may need to be recalibrated or replaced.

Step 6: Inspect the Accelerator Pedal Sensor

The accelerator pedal sensor is another component that can affect the operation of the exhaust brake. Check the sensor for any signs of damage or malfunction. If necessary, replace the sensor to restore proper functionality.

Step 7: Test the Retarder Functionality

If your DAF truck is equipped with a retarder, test its functionality. The retarder works in conjunction with the exhaust brake to provide additional braking power. Ensure that the retarder is engaging and disengaging properly. If the retarder is not functioning correctly, it may require professional inspection and repair.

Step 8: Consult a Professional Mechanic

If you’ve followed the troubleshooting steps above and are still experiencing issues with your DAF truck’s exhaust brake, it may be time to consult a professional mechanic.

They will have the expertise and diagnostic tools to identify and fix the problem effectively.


Exhaust brake problems can be frustrating, but with the right troubleshooting steps, you can get your DAF truck’s exhaust brake back in working order.

Remember to check the fuse, inspect the switch or lever, examine the solenoid, and verify the throttle and accelerator pedal sensors.

If all else fails, don’t hesitate to seek assistance from a professional mechanic. Safe travels!

Steve P.

Steve is an automotive technician, technical writer, and Managing Editor. He has held a lifelong passion for cars, with a particular interest in cars like the Buick Riviera. Steve is based in Boise, Idaho.

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