How can i check if webesto heater is working

Au2ro

Member



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Yea, it's all verry well turning it with a screwdriver when the Webasto is out of the engine bay. To move it while in the engine bay I found that I had to move the air filter that sits above the Webasto and get both hands, one either side of the Webasto, and move it with one finger from each hand. I now actually have little blisters on each middle finger after doing that today!

How difficult is it to take out to service it anyway?
 

PlasticMac

Member
I think, (can't check as no Webasto), you can test the Webasto kit with VCDS, using the appropriate (HVAC or Aux Heater I'd guess) Controller Output Tests. You'll need a registered (£75) copy of VCDS Lite for this.

Mac.
 

steveb

A2OC Donor
I have had an issue with my Webasto never coming on since I got the car .
One of the first things I did wen I got it all those years ago was drain and fill the coolant system - and that has been done a few tines since then, never knowing about the Webasto bleed screw.
I did try bleeding and the ice cube trick today, but the Webasto still never came on even though it thought that it was 5 degrees C.
I was advised to get a new glowpin/plug from a scan in the summer so I will be getting one soon to try that.

I found this link for a kit - Webasto Thermo Top E/C/P/Z glowpin kit | 9017813B But it states
"This glow pin repair kit only applies to heaters TT-E, TT-C, TT-P, TT-Z
manufactured from >2004."
and mine is a 2002. I will ask the supplier if they have the same kit for 2002 model.
I think you will findthe burner tube needs replacing as well, while you have the unit apart
 
Have you bled the hose to ensure you have not got an air lock in the Webasto water pipe
Small bleed valve/ nipple on hose under brake fluid reservoir, this fixed mine when I carried out a full fluid change recently,
Sensor for Webasto is in the lower grill use ice pop or ice cube to simulate frost/ low temp
Situation.
Hth
Keith
Can you advise if i should bleed the webasto with engine running or off thanks

john
 

kp 115

A2OC Donor
Can you advise if i should bleed the webasto with engine running or off thanks

john
I would try it when you’ve got the engine hot,
It’s quite awkward to get to, if you’ve got a small ratchet set with a flat bit might work or a pair of grips/pliers on the knurled outer ring (turning to the right when viewed from above standing at the front of the car.
Hth
Keith
 

Alfunks

New Member
I plugged a snap on diagnostic machine into the OBD you can re-set the Webasto from there when I first got our A2. Mine cuts in from 7oC and above 7oC the A/C is active I’ve never used the ECON button in the 10 years of ownership and the Webasto works every winter and the A/C is brill as a dehumidifier on damp days and nice and cold in the summer. Happy days 😊
 

413

Member
Replaced my kaput Webasto earlier this year with one from the marketplace but not been able to get it working yet. It's bled and will fire up from self-test in VCDS (no error codes) but if switch to measuring blocks when it's running all the values come up red as N/A and controller not available.

Replaced front temp sensor on the off chance but still no joy.

Any ideas if the lack of measuring block values points to some specific fault?
 

413

Member
Good thinking - found this in the Additional Heater technical manual Pinkythelabrat kindly sent me a copy of.

Current coding is 00002 but looks like there's maybe something in the adaptation settings I could try out:
1580129313966.png


.
 

413

Member
Seems my Webasto is software version D49 so can only adapt cutoff voltage and CO2 content of exhaust on channels 1 and 2.

D49 is also used on A6 & A8 and guidance gives their coding as 00001 & 00011 but say's not to use them or 00012 which is specific for when a V55 recirculating pump is fitted.

Measuring block 003 reads 'Heater off' so I may just try changing main coding to the 1 and 11 and see what effect that has.
 

413

Member
Scrub that - the A8 heater manual advises 'Heater off' in 003 means:
1580147498157.png

More digging required.
 

413

Member
It came from 'P stamp' who assured it was an A2 one - looking back on the messages see he's now showing as banned - so an element of doubt now.

Once installed couldn't get a response from it in VCDS so fitted original control unit which fires up and runs fine in test. Part shows as 8Z0815071 in VCDS. If it's a different boiler unit (like with a V55 recirculating pump) then a coding change might fix. Seems easy enough to test that and see what happens...
 

413

Member
Coding of the webasto unit was a red herring. Closer reading of the A2 additional heater manual confirms the climate control panel sends the message to the ECU to activate or switch off the Webasto. Activating the heater through VCDS bypasses the climate signal which explains why it functions there and has no faults logged. No faults on the panel but don't think webasto test is part of the output tests on it to pick up. Removed unit, and cleaned contacts but no change. Trying a different climate panel to see if that has any effect is next step. Off to the Wanted section...
 

Pinkythelabrat

A2OC Donor
David Mcluckie on YouTube recently posted a video on replacement ECU for a Webasto which turns it into a 12v signal = on like the thermotop c rather than the z/c we have. It would remove it from your control loop and you’d need to manually activate and deactivate. Pricy at £130 or so but with an additional electric water pump it would function as a parking heater.

This guy (https://maelpoureau.com/webasto_shower/) has apparently used an Arduino and some mosfets to replace the ECU entirely and make the heater run on his code. Similarly it would be a manual turn on. DM hasn’t made it work yet but might be a cheaper option.




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Pinkythelabrat

A2OC Donor
David Mcluckie on YouTube recently posted a video on replacement ECU for a Webasto which turns it into a 12v signal = on like the thermotop c rather than the z/c we have. It would remove it from your control loop and you’d need to manually activate and deactivate. Pricy at £130 or so but with an additional electric water pump it would function as a parking heater.

This guy (https://maelpoureau.com/webasto_shower/) has apparently used an Arduino and some mosfets to replace the ECU entirely and make the heater run on his code. Similarly it would be a manual turn on. DM hasn’t made it work yet but might be a cheaper option.




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413

Member
Update: replaced the electronics in the climate control panel with a donor unit from A2Steve a couple of weeks ago. Didn’t seem to have any effect but the webasto finally woke up from a two year slumber and kicked in this morning. Result.

The original climate control wasn’t showing any faults but VCDS doesn’t test the webasto activation signal in the climate output tests. So if your webasto has no fault codes and works okay on output tests this is a cheap option to try and see if it fixes it.

Easy to swap the front panel over between units and keep your good buttons.
 
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