Why webasto does not turn on: possible reasons

Webasto is an irreplaceable thing in the modern world. Happy owners of such a device in the winter period avoid serious problems. But as soon as the system goes down, to no, the question arises, why is Webasto not turned on? In the article we will try to understand the possible causes of failure, but first we will consider how to properly use the mechanism in order not to experience any problems with the heater.

Webasto does not turn on

Webasto system in the car


  • 1 What is webasto? Distinctive features
  • 2 How to use Webasto?
  • 3 Repair and diagnostics of the heater
  • 4 troubleshooting
  • 5 Independent search and problem solving

What is webasto? Distinctive features

Today it is difficult to find a car enthusiast who does not want to integrate Webasto into his car. Webasto is an autonomous German pre-heater. A compact mechanism weighing 5 kg is installed inside the circuit of the cooling system of the on-board network and the fuel system of the car. The main function of Webasto is to warm up the engine before starting the power unit. Autonomous pump heater drives antifreeze throughout the cooling network through the radiator. In fact, the device is a small combustion chamber connected to the cooling system of the vehicle. Today, the manufacturer puts on the market two types of devices - Thermo Top Evo-4 и Thermo Top Evo-5. They differ only in power.

Also, Webasto is connected to the standard cabin heater and starts the fan. Thus, in the cold season, the driver does not need to wait for the engine to warm up. The motor reaches the required temperature at the touch of a button. The owner does not need to approach the car, you can run Webasto from the window of the apartment. Also, cold start engine wear is equal to mileage of 100 km. The heater works autonomously, heating and a long start of the motor does not take a large battery charge. Of the obvious disadvantages only that the battery life is reduced by a year. If you take it as a fee for convenience and comfort, the battery change is not decisive.

Diagnosis webasto do it yourself

Webasto work in winter

How to use Webasto?

In order for the device to serve a long operational period, and you didn’t carry out a Webasto diagnosis with your own hands, you need to follow the attached instructions and tips:

  • parts of the mechanism should not come into contact with the liquid;
  • parts of the device should not be affected by electrical charges;
  • do not work at high humidity and temperature;
  • turn off the heater at the gas station;
  • use of Webasto in closed garages is prohibited;
  • use fuel supplied by the manufacturer;
  • the device must occasionally be started up when the engine is not warm at a lower fan power in the region of 10 minutes;
  • the heater can only work for an hour, do not run it often.
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Repair and diagnostics of the heater

When Webasto does not start after the summer downtime, many people think that they will easily repair the system on their own. This is far from the case, because, like any other mechanism, the heater has a twisted system. When you do not understand anything in electrics, it is worth contacting the company's diagnostic center - this will save you from more round costs. If you have an idea about the work of a mechanic and are willing to take a chance, then you should start by reading the manufacturer’s scheme. Check out the simplest parts of the mechanism, perhaps the reason lies precisely there.

Webasto does not start after summer idle

One type of webasto


Malfunctions are divided into types:

  1. Internal memory errors. As a rule, they do not affect the mode of operation.
  2. Spontaneous failures. Autostart or secondary inclusion is hidden in the device circuit.
  3. Shutdown by mistake. Failure goes to the control panel or power supply. Heating is switched off without saving the error. The second failure option, when the error persists, and the restart asks for a signal to shut down and start a new system.
  4. Webasto lock. Occurs due to repeated error. Failure must go 4-6 times and then the unit is blocked and saves the report. It is impossible to unlock the mechanism by yourself; you should contact the service center. Note that if the malfunction is due to low voltage or a damaged battery, there is no lock.
  5. Overheating lock. When Webasto overheats, the system is blocked.
  6. Shutdown by mistake due to low or high voltage. When the voltage reaches 11.5V, the mechanism turns off for a while. After there is a purge. Measure the voltage can be a control unit. When the voltage is too high it is measured by the heater. Usually, at 16V voltage, the operation is suspended, and shutdown and purging are in progress. If the problem is solved, the system is again ready to serve.

When Webasto does not start, reasons of a different nature are determined using Thermo Test PC diagnostics.

Elimination of errors.

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Causes of common failures are collected by type:

  1. Not saved errors. First check the fuel supply, and only then change the heater or connecting nodes.
  2. Fixed crashes. Look at the type of problem in the device's memory, it shows the faulty node. Next, eliminate the damage by replacing parts.
  3. General saved crashes. When Webasto did not identify the broken part of the system. First look at the peripheral parts of the mechanism.
  4. See information about the error using the PC-diagnostics.Webasto does not start

    Pc diagnostic webasto

Independent search and problem solving

Fuel. Often problems lie in the supply of fuel. It happens in the winter, when many drivers forget to change the summer diesel to winter. See the heater, can earn in a warm room, so take care of the garage. When the webasto in a warm place is gone, change the fuel. First, lower the diesel, blow through the system, clean it, change the filter, pour in the new diesel. There is another reason for not entering the fuel heater. Diesel does not reach the pump. The sound is clear and loud. There may also be air leaks when the fuel wire is damaged. In addition, you need to check the solenoid valve, there is a congestion in it. To check the air pressure on the winding take an ohmmeter. Normal units range from 136-154 ohms. When performing diagnostics, feed any flushing fluid into the tube.

Rang electricians. After checking the fuel system, people who understand electrics go further, and the average drivers turn to service craftsmen. We look at the fuses F1-F3, if there are blown ones, we make a replacement and check for operability. Next, check the timer. We measure its current in the connector, if there is no current supply, then the timer should be changed completely. The next control object is the stove. We look at the terminals at the same time, when they are oxidized, it can block the supply of current. We look at the integrity of all wires. Depressurization most often occurs on the plug itself.

Webasto does not turn on

Instruction manual webasto

Remove blocks. Webasto can turn on the lock due to the fact that the errors are corrected, and reports about them did not have time to fit into the memory panel. From the BU for 3 seconds we remove the powerby unlocking it. We take out the chip and return it to its place. After turn on the heater. Then we repeat the first two points of manipulation. If everything went well, the system will work.