Eberspacher Diesel Heater - Fault Code P000300

combatklp

Member
Looking for some thoughts from the Hive Mind here....

Eberspacher Diesel Heater (which was working fine). Now throws up a fault code on the controller of P000300. Attached is an image from the troubleshooting manual.

So far we've,

1. Replaced the controller with one from another van - same error.
2. Removed the Diesel Heater, and put it on a test bench - works fine.
3. Checked and traced the wiring loom to look for shorts / breaks in the cable - found a very small nick in the rubber sheathing of one tiny wire in the loom, which heads inside the van. It had been rubbing on a component (dodgy installer I think). The nick is not through to the cable itself, so I thought unlikely to be the issue - repaired anyway - the same fault.

Now the troubleshooting guide seems to suggest, that the loom / harness is most likely, in this case, maybe more so, as clearing the fault codes to 'unlock the control box' has no effect.

The temperature sensors on the control unit, and the air sensor both work and read correctly (as can be viewed on the display of the control panel).

So before we bite the bullet and order a new loom, any thoughts?

This is my dad's van, he's nearly 70 and this is his lifeline - he absolutely depends on the diesel heater in these cold conditions - so your help is greatly appreciated.

Thanks,

L

WhatsApp Image 2025-01-25 at 13.21.25_8ce2f043.jpg
 
I had the same sort of thing on a new Webasto - I traced the fault by checking every wire for continuity and found a break eventually. So my advice is to check every wire for continuity.

broken wire.jpg
 
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