Diesel Heater E10 Error Code (3 Causes and Fixes)

Diesel heaters are quite complex. Faults can be anywhere in the fuel pump, the blower, the glow plug, or the electric supply.

So, when your diesel heater shows an E10 error code without any context, you usually have no idea where to start looking.

This article serves as a reference for the E10 error on diesel heaters. We’ll have a look at what the E10 code means, different reasons for the issue, and how to fix all of them.

After reading this article, you will have a thorough understanding of what’s going on with your diesel heater, and – ultimately – you know what to do to fix it.

What does the E10 Error Code on a Diesel Heater mean?

The E10 error code represents a generic startup issue. E10 serves as a fallback error code if your heater can’t identify the exact cause.

Because your diesel heater doesn’t know what causes the startup issue, you have to inspect the heater yourself.

But the fact that your heater can’t identify the issue is already valuable knowledge for us. It means that the issue is in some unmonitored component of the heater, likely one of the following:

  • Electric power upon heater startup
  • Lack of fuel reaching the heater
  • Combustion problems

How to fix the E10 Error Code

Let’s have a look at each of the causes in more detail and find out how to fix each of them.

1. Electric Power Issue

To start the combustion, your diesel heater needs sufficient electric power. If the power supply / car battery you’re powering your heater off supplies less too little electric current, the glow plug can’t ignite the diesel in the combustion chamber.

Upon starting your diesel heater, for a short moment, it draws a large current from the battery, which causes a temporary voltage drop. If the voltage drops too low while powering the glow plug, it can result in an electronic circuit issue that prevents the onboard electronics from working properly.

After multiple tries, your heater displays the E10 error.

In any case: A well-charged battery should be able to power the heater.

How to check it:

  • Test the Power Supply: To test for an electric power issue, you can connect your car battery to a digital multimeter while trying to start your diesel heater. Before starting, the voltage should be >12V. Then, while starting, the voltage shortly drops and jumps up to 12V again.
    If the voltage is consistently below 12V after starting the heater, your car battery is too weak to power it.
  • Check Electric Connections inside the Heater: Also, ensure that all electric connections are fine. Disassemble your diesel heater and trace the electricity going into it. Make sure no connections are broken or corroded.

How to fix it:

  • Charge Car Battery: Ensure your car battery is properly charged.
  • Use a New Battery: If it still doesn’t work, retry with a new car battery.
  • Try DC Power Supply: If it still doesn’t work, try a different 12V power source, such as a variable DC power supply.
    Some diesel heaters come with a transformer that allows you to power the heater off a regular 110V wall outlet. Try that.

If all of that looks fine, the issue is likely something other than the electric circuitry.

How to workaround the issue without fixing it

Start your diesel heater while the engine is running. This obviously only works for diesel heaters in vehicles.

With a running engine, the power supply should be a solid 12 Volts. Once the heater runs, you can turn the engine off again.

2. Fuel Problems

If no fuel is reaching your diesel heater, it obviously can’t start, which causes the E10 error. Let’s have a look at the most common issues that cause a lack of fuel supply in your diesel heater.

How to Check It:

  • Fuel Level: First, ensure there’s enough fuel in the tank.
  • Pump Function: Listen to the fuel pump during start-up. A healthy pump should produce a consistent, rhythmic sound. Irregular or no sound can indicate a problem.
  • Inspect Fuel Line: Look for any kinks, damage, or excessive length in the fuel line. A hard nylon line can resist kinks better than softer materials.
    But a soft fuel line works just as well if it has no kinks and dents.
diesel heater fuel pump
Check the fuel pump!

How to Fix It:

  • Refuel: If the tank is low on fuel, refill it.
  • Pump Repair or Replacement: If the pump is faulty, it may need repair or replacement. Check the electrical connections to the pump as well.
  • Pressure Adjustment: For pressure issues, adjustments can often be made on the pump (if it has adjustable settings) or by clearing any blockages in the line.
  • Fuel Line Optimization: Lay out your fuel line in as straight a line as possible.
    Shorten your fuel line if it’s too long.
    A long fuel line requires more pressure to work. The shorter your fuel line is, the better it works. Switching to a hard nylon line can prevent future kinks and bends, ensuring consistent fuel delivery.

How to workaround the issue without fixing it

In some cases, you can temporarily get your heater running by ensuring it’s on level ground (to aid fuel flow) or tapping or knocking against the fuel pump to kickstart it. However, these are only short-term solutions and won’t resolve underlying issues.

3. Glow Plug and Burning Chamber Issues

Diesel heaters oftentimes don’t monitor the combustion process, which results in the E10 error when something goes wrong.

How to Check It:

  • Disassemble: Disassemble the heater to access the glow plug and burning chamber.
  • Examine the Glow Plug: Look for signs of soot, carbon buildup, or physical damage on the glow plug. A clogged or dirty glow plug can’t ignite fuel.
  • Check the Burning Chamber: Similarly, inspect the burning chamber for any dirt, soot, or obstructions that could impede its function.
  • Atomizer Screen Assessment: The atomizer screen, which converts liquid diesel into a mist, is crucial for proper combustion. You can find it near the fuel inlet inside the combustion chamber of your diesel heater
    Ensure it’s clean and free from blockages.
  • Air Intake Inspection: Verify that the air intakes are clear. Restricted airflow can lead to inefficient combustion and contribute to issues with the glow plug and burning chamber.
diesel heater clogged exhaust vent
A clogged exhaust can look like this if something went really wrong. It’s unlikely to happen, but make sure all airways in your diesel heater are free.

How to Fix It:

Fixing these issues resolves mainly around cleaning the parts properly. To do that, either use a toothbrush or a fine wire brush, or compressed air.

You can use Brakleen brake cleaner for more thorough cleaning of the glow plug and atomizer screen, especially for removing stubborn carbon deposits.

  • Clean the Glow Plug: If you find dirt or soot on the glow plug, clean it thoroughly. In cases of severe damage or wear, consider replacing the glow plug.
  • Burning Chamber Maintenance: Clean out any debris or soot from the burning chamber. Ensure it’s free from any obstructions that could affect the heater’s operation.
  • Atomizer Screen Cleaning: Carefully clean the atomizer screen. A blocked screen can significantly impact the efficiency of fuel combustion.
  • Clear Air Intakes: Make sure the air intakes are completely free. For this, a compressed air gun is ideal.

How to Prevent the E10 error in the Future

Here are some advanced, but very useful tips to keep your diesel heater working without issues in the future.

  • Fuel Line Insulation: Insulate your fuel line, especially in colder climates. This prevents the diesel from gelling, a lesser-known cause of fuel flow issues that can trigger the E10 error.
  • Custom Fuel Mix: In extremely cold temperatures, mix a small percentage of kerosene with your diesel fuel. Kerosene can lower the gel point of diesel, improving flow and combustion efficiency, thereby reducing startup issues.
  • Pre-Start Lubrication: Occasionally, use a diesel fuel additive that includes lubricants. I recommend Hot Shot’s Secret Diesel Winter Anti-Gel additive (click to see it on amazon). This can help maintain the smooth operation of internal components like the fuel pump and atomizer, which are crucial during startup.
  • Battery Direct Connection: For heaters struggling with power issues, connect the heater directly to the battery using high-quality, thick-gauge wires. This bypasses any potential voltage drops from the vehicle’s wiring harness.
  • Exhaust Backpressure Check: Occasionally check the exhaust system for proper backpressure. Incorrect backpressure can affect combustion, leading to errors. Adjusting or replacing the exhaust silencer can rectify this issue.
hot shots secret diesel heater anti gel additive
Try diesel anti-gel additive. It will make a difference whenever it’s cold.

What to do if you can’t fix the E10 error?

If you can’t fix the E10 error code, and it keeps showing, maybe the E10 error code has a different meaning in your particular diesel heater model.

I suggest looking up the manual. See if there’s a list of error codes and their associated meanings. If you don’t have the manual anymore, you can usually find it online, looking for your heater model number + manual.

Also, have a look at my diesel heater repair article: How to fix a diesel heater not getting hot

And if that doesn’t help, just get a new diesel heater. The issue might be somewhere in the electronics or in another hard-to-repair part.

I recommend getting this Vevor diesel heater (click to see it on amazon). Or, if you find it too strong (it’s 8KW), get the smaller 5KW variant. I find 8KW the better choice in most cases. Better to have too much heating power than too little. You can, of course, adjust the heat setting.