AUX Waterpump Short Circuit against U-BATT
 

Can anybody help solve this issue?

my aux waterpump is not working.

First thing I did was change it out with a brand new one, and still same error code.
I have checked fuses, and I have traced the wires back as much ass possible looking for a short circuit. everything is in tact.

Webasto is working fine but since the pump doesn't work webasto is useless.

HELP?!

Need a little more info. - like year and engine? I'm guessing it's a diesel (M57) since it has Webasto.

But FWIW, it appears that in the cars fitted with a Webasto heater the aux water pump runs from the Webasto. In cars with no Webasto, the aux pump runs from the IHKA.

Since you have a Webasto, you need to check that the aux pump is getting power from the Webasto and that the Webasto is in fact working correctly. Check Fuse 59 behind the glovebox...

What error code are you referring to?

Yes it's the M57 its a 2005 3.0D facelift

All the fuses are good and the webasto works. it fires up when I unlock the car and I can feel it heating up.

anyone have a wiring diagram for the webasto so maybe I can trace the short to the internals of the webasto.

this is the error, it's in German for some reason my inpa is in english but all the fault codes are german.

Variant: IHKA39_5 1 Error in error memory
Error registration 1 : 0x001E: Zusatzwasserpumpe
Error accurances: 254
Kurzschluss gegen U-Batt
--
--
--
Fehler momentan vorhanden
--
<<<<!!!

Error code: 1E 41 FE 48 42 88 FF 49 04 03 8D

Zusatzwasserpumpe = Auxiliary Water Pump

Kurzschluss gegen U-Batt = Short Circuit Against -U-Batt

Fehler momentan vorhanden = Error Currently Present

Circuit diagram for heater system is here: -

https://www.newtis.info/tisv2/a/en/e...g-pump/h4T4VDL

Unit A14 is the Webasto. I would try unplugging connector X642 (power to the Webasto) then clear the errors and see if they stay away. It could be an internal fault in the Webasto (Short Circuit Against -U-Batt) or a worn/chaffed wire on the Webasto or Aux Pump wiring... :dunno:

Like said previously on models with M57 engine or any other E53 model with factory Webasto the supply for that water pump comes directly from Webasto control card. On versions without Webasto the supply comes from IHKA. On your vehicle that code for aux water pump is from IHKA. So IHKA is coded wrong regarding this aux water pump though is shouldn't cause any symptoms. Does your car has pre-heating option from the factory or was was it coded afterwards? Is it possible that IHKA has been changed at some point?

If you have NCS expert this can be rectified by coding IHKA.

ZUSATZWASSERPUMPE
aktiv -> nicht_aktiv

Thanks for the info, I'm not sure if the previous owner did any coding on it but I have now used NCS expert to code out the waterpump on IHKA.

this still hasn't fixed the issue of the waterpump not actually turning on though.

Then I would code the units (at least IHKA and instrument cluster) again with default values according to ZCS/FA (basic SG_CODIEREN coding).

So do you have the pre-heating option or do you want to add it too? For this you have to change ZCS, then code IHKA and instrument cluster. Then you manually (FSW_PSW) have to change IHKA coding for change over valve because a version without pre-heating from the factory does not have it.


536 (SA) 0000000000020000 STANDHEIZUNG

STANDHEIZUNG_KONZEPT
sh_high_ohne_sperrventil (high/low according to high or low OBC)

The thing is I have an android head unit with iBus. I'm not sure what system it had originally. I have the option for aux heating in iBus.

Also I live in Cyprus, so it doesn't really go below 6 degrees C apoart from some winter nights. I understand the pre heating is only supposed to work below 6C but I thought the aux water pump should be running when the car is at idle to circulate the coolant through the heater core? basically when I'm at idle the heat in the car drops significantly

So not much need for pre-heating option. So do just that default coding without adding 536 to ZCS. If after those coding the water pump doea not activate when ignition on the control card on Webasto must be failed and not giving voltage to aux water pump.