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How to Reset an Exhaust Fluid System Fault on a Ford Diesel Truck? (Step-by-Step)

Updated: Jan 8

Exhaust Fluid Systems (DEF) are designed to reduce emissions in diesel engines by breaking down harmful nitrogen oxides (NOx) into harmless water and nitrogen.


However, if there is a fault in the DEF system, it can cause problems with the engine and result in a warning light on the dashboard.


To reset an exhaust fluid system fault on a Ford diesel truck you can use an OBD scanner or you can disconnect the battery for a few minutes to reset the fault.


In this article, we will explain what causes DEF pump failure and how to reset an exhaust fluid system fault on a Ford diesel truck.

 

Table of Contents:


Ford diesel truck

What Causes DEF Pump Failure?

There are several factors that can cause DEF pump failure in a Ford diesel truck.


  • Contamination with hard water: If the DEF fluid becomes contaminated with hard water, it can cause crystals to form in the pump, leading to failure.

  • Contamination with diesel fuel: If the DEF fluid becomes contaminated with diesel fuel, it can cause the pump to fail due to the different properties of the two fluids.


How to Clean a Contaminated DEF Tank

If your DEF tank or pump becomes contaminated you can use a vinegar solution to clean it out.


  1. Mix three parts water and one par vinegar.

  2. Pour this solution into the DEF tank.

  3. Run the truck for about 30 minutes to allow the solution to clear out the pump.

  4. Empty the DEF tank and refill it with fresh DEF fluid.


How to Reset an Exhaust Fluid System Fault on a Ford Diesel Truck

If you are experiencing an exhaust fluid system fault on your Ford diesel truck, there are a couple of steps you can take to reset the fault.


  • Use an OBD scanner: One way to reset the fault is to use an OBD scanner to clear the error code. This is a device that plugs into the vehicle's OBD port and can be used to diagnose and reset faults in the engine management system.

  • Disconnect the battery: Another way to reset the exhaust fluid system fault is to disconnect the battery and then reconnect it after a few minutes. This can reset the engine management system and clear the error.


How Do I Reset My Ford DEF Sensor?

To reset the exhaust fluid system fault on your Ford, try these steps.


  1. Fill the DEF tank with at least one gallon of DEF.

  2. Allow the car to idle for a few seconds before driving at a low speed until the warning sign disappears.

  3. If this doesn't work, try resetting the engine system by disconnecting the negative battery connector and waiting 20-30 minutes.


How Does DEF Work in a Diesel Engine?

DEF is injected into the exhaust stream of a diesel engine where it reacts with the NOx emissions to break them down into harmless water and nitrogen. This helps to reduce the amount of NOx emissions released into the environment.


How Often to Refill DEF Fluid

The frequency at which you need to refill DEF fluid will depend on the make and model of your vehicle and your driving habits.


As a general rule, you should check the DEF level regularly and refill as needed.


In most cases, the DEF tank will need to be refilled roughly every 5,000 to 8,000 miles (8,000 to 12,800 km). To keep on top of it, refill it every third or fourth time you fill up the diesel fuel tank.


What Happens if I Run Out of DEF?

If you run out of DEF, it can cause the engine to enter a "limp home" mode where the power is reduced to protect the engine from damage.


This is because the DEF system is no longer able to break down the NOx emissions and the engine will produce higher levels of NOx, which can be harmful to the environment.


Do You Need Diesel Exhaust Fluid?

Yes, diesel exhaust fluid (DEF) is a necessary component of a diesel engine's emission control system. It helps to reduce the amount of NOx emissions released into the environment by breaking them down into harmless water and nitrogen.


What Happens if You Don’t Use Diesel Exhaust Fluid?

If you don't use diesel exhaust fluid (DEF), the engine will produce higher levels of NOx emissions, which can be harmful to the environment.


In addition, the engine may enter a "limp home" mode where the power is reduced. It is important to use DEF as directed in order to keep the engine running as it should and to meet emissions standards.