Diesel Heater - False Low Voltage Error E-2

[barbtalon]

My 2 kW diesel heater is giving me an E-2 error. The manual says that this is a battery supply voltage error. My heater will not start, and it will not prime either. When I try to either start or prime it, the screen flashes P04V. I'm assuming that this means that the controller thinks that there are only 4V supplied to the motherboard.

Okay cool, so I'm now thinking it's a faulty power-supply wire between my battery bank and the heater. I check the voltage at the motherboard, and it's a healthy 12.1 V. What's the deal? I can only think of two possibilities:

1. Faulty motherboard.
2. Faulty control unit.

I also checked a few other things too:

The voltage at the fuel pump connector is 4.3 volts.
The voltage at the fuel pump nodes on the motherboard is also 4.3 volts.

From past experience, I believe that the 4.3 voltage at the fuel pump is what it is supposed to be. Even if that's not the case, the solution would still be a new motherboard/controller.

Has anyone else ever had this "false" reading of low voltage coming from the controller?

Link to my type of heater:
https://www.ebay.com/itm/1862170398...qhHkmPx5v3CeSQJvFrZJaYhMM=|tkp:Bk9SR-av66DLYw

Link to another thread that also makes me think it's the controller/motherboard at fault:
https://diysolarforum.com/threads/chinese-diesel-heater-does-not-start-no-voltage-displayed.76579/

 

[OM617YOTA]

Have you checked voltage while the heater was trying to turn on? The extra draw from the glow plug could cause voltage drop in marginal wiring or a loose connection, even if it looks fine when just sitting there with minimal load.