A2 Auxillary Heater - Fuel pumps tests ok but will not run in auto

M

mike carvell

New Member
When i test the fuel pump via VCDS it runs perfectly, but run a test on the heater or put it on auto the pump does not click.

I have checked through all the threads and connot find a solution, has anyone else had this issue?
 
Is the air intake fan on the Webasto spinning up first. The turbine will normally start first and then the glow plug will go on before the fuel pump starts I think. If either fail the self test it won’t pump.


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Pinkythelabrat said:
Is the air intake fan on the Webasto spinning up first. The turbine will normally start first and then the glow plug will go on before the fuel pump starts I think. If either fail the self test it won’t pump.


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Yep, spins up as it should and tests out OK with vcds
 
Part of the climate control unit sends the activation signal to the Webasto - the VCDS test bypasses that and gets it to fire up . Mine would work fine in test but never in real life. Fixed last winter by putting another CC unit in. Inevitably this winter it's gone back to not working. It's an integrated sensor on the circuit board - could be as simple as the soldered joint drying up but yet to track down a wiring diagram for the CC unit to try and work it out.

Shame there's not just a dashboard switch to activate the webasto.
 
I think I agree with 413. If it’s doing all the right things with VCDS but not when controlled by the car then it sounds like an activation problem rather than a Webasto problem.

Is your temperature sensor in the car reading 2C? Maybe it’s seeing higher?

Is the ECON button able to toggle on/off - does it make a difference?

Is the battery charge good?


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Thanks for replys.
When cold enough it does go through start up on auto, but the pump has no output, pulled off fuel pipe on heater, pumps out ok on test though.

Perhaps need to get circuit board out as suggested.

Thanks all
 
According to the A2 webasto manual it is connector D, contact 10 on the E87 climate unit that sends the signal. There's also the circuit board and connector on the webasto itself but the climate user is a doddle to get to compared to that.
 
Does anyone know if a G263 sensor fault (the really difficult to get to interior temp sensor), will cause the Webasto to not work? I have the G263 open /short fault code but no fault codes on the webasto, and the webasto is dead, no nothing, no pumping, whirring...I don't want to start investigating the webasto if its something else blocking the activation... cheers nod
 
G263 isn't mentioned in the A2 additional heater manual but that's very focused just on the webasto unit itself. If there's a similar manual for the E87 climate control that might have more clues?
 
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Have you looked at what temp the webasto thinks it's seeing, mine is seeing a temp of 110deg. with the engine cold so it wont start, i haven't yet removed it to check the internal sensor.


Cold .jpg
 
Good point - think I've seen mine say something similar to that when testing this winter as well.

According to the manual:

The temperature sensor (for the coolant temperature in the heater) is permanently installed (in the heater control unit -J162) and can neither be checked nor removed.

J162 is the whole circuit board in the control unit on top of the heater - can't think of a more inconveniently placed bit to try and get at in bad weather.
 
This is the circuit board from a spare non working unit I have, the sensor is the small white bit to the right of centre top.
 

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Just found this -

From that it does seem repair is possible - only a component on the board after all - but it's sketchy on details. Some sort of NTC 10k ohm thermistor. No reference number on the OEM part:
thermistor.jpg


Prime Timmus or Depronman repair territory? I'd certaintly like the next time I take the webasto out to be the last time...
 
Also worth checking the solder is in good condition and no signs of corrosion or water ingress and the board is not cracked due to vibration.

Is the component available from RS?
 
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