Touran Auxiliary Heater Error 01412

"I occasionally receive the following error message:"

01412 - Spark plug with flame monitoring (Q
008 - implausible signal.
Environmental conditions:
Error status: 01101000
Error priority: 3
Error frequency: 2.
Lost Count: 226
Mileage: 125781 km
Time: 0.

Environmental conditions:
text
Start
Temperature: 46.0°C
Temperature: 45.0°C
Voltage: 11.56 V

- Sometimes the auxiliary heater runs for 30 minutes.
- Sometimes he stops after just 3 minutes.
I had already disassembled and cleaned that part before. It worked a little better then.
But still not 100%.

I once measured the glow plug's resistance: the initial resistance was 0.36 ohms.
Then I turned on the auxiliary heater.
The resistance increases with the applied power (from 0.36 ohms to 0.85 ohms).
The target value is between 0.18 and 0.26 Ohms.
Does this indicate a defect?

What I've also been thinking about is:
- The shutdown threshold is at 11.3 volts. When it's running, I measure around 11.5 volts.
But if that were the reason, then there would be a corresponding error in the memory.

This isn't really reproducible.
I'm a little hesitant about getting a new heater (€625). But eventually, it should work .

Quote:

The resistance increases with the applied power (from 0.36 Ohms to 0.85 Ohms). The target value is between 0.18 and 0.26 Ohms. Does that indicate a defect?

Well, the fact that the resistance increases when a candle is heated is probably just due to the nature of the material.

An extra 0.1 ohms could also be due to the measuring device... but not necessarily.

If it's still the first spark plug, you could proactively replace it before trying to diagnose any other issues.

This is the typical story with the Touran's auxiliary heater. You need a new combustion chamber insert. The part number is 1K0261433C or D for the TDI, depending on the vehicle's chassis number.
Have the parts specialist look it up for you. The glow plug is included with it. Please don't call me early in the morning while I'm still in my pajamas about this, but for the diesel Touran heater, the glow plug wasn't available separately. Unlike the gasoline heater, it was only sold as a complete combustion chamber assembly.

Spare parts for the factory-installed Touran heater are only available from Volkswagen. They are not distributed through Webasto dealers. While a Webasto dealer might be able to obtain it for you, you won't save any money compared to buying it directly from a VW dealership in that case.

Don't forget to order the sealing compound if you're assembling it yourself.