E53 Aux Heater faults again

[mashby]

I am a newbie to forum but have spent hours viewing above faults on my 55 plate E53 diesel heater.

Read many posts about faulty PCB's, faulty resistors caused by capacitor sealing compound, etc. My 55 plate e53 will fire up but stop after 2 mins with erratic fan motor & then shut down then loads of smoke. Haven't cleaned it yet but suspect faulty PCB. I do not have remote so activates as it should below 5 DegC with engine cold.

Any thoughts. INPA shows a  Combustion Fan Interrupt when motor shuts down. Not sure if this is a result of a flame out or faulty PCB??

Fan will restart during cooling cycle if error code reset by INPA.

Anyone got a spare PCB to try?  My Webasto part number is 9003552B, BM No 64.12.6918942.02

Am able to replace possible faulty resistors on PCB but was wondering if fault is more likely to be caused by possible flame out caused but carbon build up. Haven't stripped unit yet?

Have tried to get contact details for French Mike the PCB expert but failed.

Anyone got any thought.

Mark A

[fenj66]

mark,
does the unit run normal when you start and drive the car on a cold morning, i.e. you can hear the clicking of the webasto fuel pump as you drive?
or is this fault situation happening when you try to run webasto by manualy turning it on with car not running?....

[mashby]

Thanks for reply. Only happens when run in cold weather. I have no manual override. i.e do not power up pin1.

[chrisn7]

Given the age of the car, I would certainly clean out the carbon first, since this might solve your problem and be worth while doing anyway. I did this recently on my 2006, with just 57k on the clock, and there was a fair amount of carbon. Dismantling is straightforward, but cleaning the mesh in the burn chamber is fiddly, and the mesh easily damaged. Your symptons are similar to those I had, solved with a replacement board that has had the required components changed

[mashby]

Thanks for comments.

I am planning to strip & clean as I suspect that fault is caused by flame out (for whatever reason) so smoking after wards is a result of the fan motor being shut down & locked out?

[ScottBarton]

[quote="fenj66"]
mark,
does the unit run normal when you start and drive the car on a cold morning, i.e. you can hear the clicking of the webasto fuel pump as you drive?
or is this fault situation happening when you try to run webasto by manualy turning it on with car not running?....
[/quote]

That is what the clicking is!!! I thought I had a fault when I heard this for the first time. Nice to know that its normal.  )