Hey guys,

Since this is my first ever thread, hi everyone, I'm Alex from Vienna/Austria I'm the (3rd) owner of a imola red 2004 4.8is, little bit more than 170k km's or 105k miles, pretty much stock except for a Android radio and now the parking heater.

This forum is such a valuable source of information and knowledge, so I wanna share the outcome of several weeks of work, sweat, dirty hands, scratched skin, burned nerves, online research and more with you. I think nobody ever did that before, at least I didn't find a single write up anywhere about a complete retrofit of a OEM heater in any E46, E38, E39 or E53 BMW. Well, except for one russian BMW forum where (I think) a guy described something like a retrofit - but this was translated by google, so Jeee, nobody knows for sure

Okay, yet not 100% finished, but at least more than 50% working, I completely retrofitted a Webasto Thermo Top C/Z heater in my 04 4.8is. In other words, it's a factory like installation with all components you usually find if you order a new car with this option.

If some of you are aware of the E53 3.0 Diesel versions, these came with a factory installed so called "Zuheizer" which is basically nothing else than a limited parking heater, which only starts if it's below +5°C and the engine is cold. This one is easily upgraded to a full parking heater by simply changing a few parameters in the IHKA and the KMB/IKE. Since my 4.8is wasn't ordered with this option, I had to go the hard way.

Parts needed:

Webasto Thermo Top C/Z parking heater out of a '05 X5 3.0D (yes, Diesel!)
E53 Heater mounting bracket
Webasto fuel pump (or metering pump or dosing pump)
E53 Fuel pump mounting bracket
E53 Exhaust
Webasto Gasoline burning chamber for the Thermo Top heater
Around 5m of fuel line (none OEM!)
E53 fuel tank intake connector (OE Part 16116752909)
Fuel pump wiring line (OE Webasto part)
Webasto T90 remote control
Some 2nd hand coolant lines from my mechanics "waste yard"

You might ask "why the Diesel heater?". Simply, there are almost no OEM BMW gasoline heaters out on the market but since all 3.0D models were delivered with this heater, it's easy and quite cheap to get one of those. The difference between the Diesel and Gasoline heater is just the burner in the heater. That one fits from any Webasto TTC unit. According to a guy who's fixing TTC units, even though the start up program in the heater ECU is different between Diesel and Gasoline units it doesn't matter, they work. So why bothering.

Why I took a OEM BMW heater? Because it's communicating via the K-BUS with the IHKA and KMB so (according to my wild phantasy) one should(!!) have no issues getting it to work. Well....

Okay, so the most fun part was actually installing the fuel line. It's like changing the fuel filters on the E53, you have to almost completly disassemble all the plastic covers on the bottom of the car. Since the fuel pump (or dosing/metering pump) has to be installed there, it makes sense to change the filters at that time too. Pump installation itself is no big deal, just 2 scews and you're done.

Really tricky is only the part where you need to get the fuel line up underneath the rear bench. The place for the intake line on the fuel tank is at the EU/US passenger side where the in tank fuel pump and level sensor is located. There you find a sealed nipple which is easy to cut open with a knife.

Mounting the heater itself is as easy as can be, fitting the exhaust not so much. You need to basically remove all the inner fender on the driver side and fiddle this thing up. If you don't remove the trim but try to pry away the plastic, you end up like me - exhaust is where it should be, but I broke a plastic part of the inner fender trim.

Since I didn't buy the factory installed coolant lines, which are of course different if you have the heater option, it's a bit of fiddling and fitting to set up your custom designed ones. I think I now got one hose from a Mercedes and part of a Volkswagen coolant line installed in my X5.

For the electrical part: 0 work - I mean really NOTHING to do, except connecting some plugs. Everything is factory pre-wired, even the fuses are all already there. So all you gotta do is plug in the connectors. Even the electrical connector for the remote control box is already there - you'll find that one under the plastic cover next to the battery in the trunk.

Now for the coding:

The problem with this retrofit is, that since the car doesn't know that there is a parking heater installed, it will not talk with it. Neither will it switch on the AC fan or anything else when needed (at least that's what I was told).

Only solution: Enter a new ZCS (or FA (FahrzeugAuftrag), which means sth like "vehicle order" on newer BMW's) and change the base DNA of the car. In case of my '04 4.8is the ZCS is stored in the EWS and KMB module.

In the E46 fanatics forum is a really good thread about this topic...
https://forum.e46fanatics.com/showth...659314&page=17

Some say you have to re-code every module in the car after changing the ZCS, others say that this is way to dangerous and you can mess up a lot of stuff by doing so. I personally only re-coded the IHKA, KMB, ZHZ and EWS with a empty .man file. These are the modules that have to deal with the parking heater and/or the changed ZCS code, so I didn't see any need for coding other modules too.

Still, there are some parameters that should be changed AFTER RE-CODING in both IHKA and KMB which are:

KMB:

STANDHEIZUNG
aktiv
ZUHEIZBETRIEB
bm_ab_pu96
ohne_bm

IHKA:

STANDHEIZUNG_KONZEPT
sh_high_ohne_sperventil
ZUHEIZER
k_bus
ZUSATZWASSERPUMPE
aktiv

One thing is for sure, if you're flasing only the KMB with the new ZCS code, it will not work, eventhough almost all the configuration for this option is stored there. The EWS has to be flashed too. I was scared to mess up the EWS, so I've tried it only with the KMB - it really didn't work

Problem I'm currently facing: The heater is basically working, it starts by switching it on with the remote control, the IHKA switches on the interior fan too, just I don't get that menu item for "Standheizung" or "Parking Heater" on my BM display. But since I'm using the IBUS App and a USB to IBUS interface so I have the BC functionality on my Android radio, the issue might be somewhere there.


I'm sorry not being able to share pictures, but my hands were damn dirty most of the time, so neither did I want to touch my phone nor my brand new Sony camera *lol*. BUT - most of the stuff is better to be seen in the BMW parts catalogue anyhow.

If there questions from anyone, I'll try to answer them at my very best - still I can't promise anything. I mean, I was scared to death and sweating while hitting the "codieren" button in NCS Expert when I flashed the EWS, so you see I'm not a specialist too *lol*

Kind regards from Vienna, merry Christmas and a happy new year,
Alex

P.S.: I might edit this post if I find some additional valuable stuff while finishing the project of if I find an error of course - just to have that said!