Installing SMEG+IV2 headunit in 2010 Citroen C3

I drive a 2010 Citroen C3 with 1.4HDI engine. From factory it was equipped with the basic RD4 radio and EMF-A display:

It had no Bluetooth, no support for anything other than CDs, AUX input and FM radio. But controls behind steering wheel worked! I bought my car used, around 2021. Previous owner has replaced the stock headunit with some aftermarket Bluetooth radio. It worked, but it didn't support controls behind the steering wheel. So I replaced it with stock unit. Now everything should work, right? No! PSA-group cars have a VIN whitelist embedded into their headunits. If there is a mismatch between the BSI module and the headunit, the unit will very annoyingly beep every second. Loudly. The remedy is to program the headunit with VIN of the car. For this I had to buy a "Lexia cable". It plugs into OBDII plug in the car and in there you can change various things. Mine came with Diagbox VM (used to program the car modules). I found the version v7.57 of Diagbox works the best for this car (more on this later!). There I could reprogram my radio with the VIN of my car. Some online sellers offer to reprogram the VIN when you buy the PSA-group radios from them and I recommend this if you are not experienced with car reprogramming.

Now, the unit was working and I was happy. But, while it worked, it lacked some features we today take for granted in a modern car: notably bluetooth connectivity for calls and music.

RD45

That's when I ordered the RD45 unit with EMF-C (type C) display. It looks something like this:

It has all the features of the RD4 unit, plus it has external microphone support for handsfree calling and Bluetooth connectivity. And it has a nicer display. It was mostly plug-and-play, of course with VIN programming needed. The only wiring I had to do was to plug the microphone in. I bought the microphone from Alixepress:

I wanted to retain the AUX support, so I needed to rewire the connector that goes to the headunit. This diagram came in handy:

We are interested in the B-part of the connector. Microphone should be wired to pin 3 and 9, white wire to pin 3, black to pin 9.

I have also bought the USB socket for the unit:

It came with the cable that needs to be connected to the headunit. After all that everything was working! I had FM radio, CDs, AUX and Bluetooth! Hands-free calling also worked!

Chinesium

But as always, the appetite grows while eating. Now I wanted a fancy screen with Android Auto/Apple Carplay support, GPS navigation etc. So I bought a chinese headunit that came with new silver trim (it needs to be replaced to allow for bigger screen). After following the instructions everything worked! Success, right? Well, it worked, but for like 8 months. Recently it has died. Randomly. It was working a day earlier. What a waste of money... Especially that it is so expensive! I paid $400 for my unit on Aliexpress! So back to the RD45 I was...

RT6, RNEG, SMEG, NAC? What is all of that?

But not for long. I got used to Android Auto and to having a navigation in the car. But I didn't want to buy another Chinesium BS. Then I started researching what other options Citroen offered for my model. As it turns out for my model year there were 3 options:

• RD4
• RD45
• RT4

Apart from RT4 I had every one of them. And the RT4 was a navigation unit! But, unfortunately, it was a navigation unit from 2010. So, no more map updates and the unit does have Bluetooth but only for calls! So it would be a downgrade from the RD45, at least for me. That's when I started researching units for newer model years. From 2011 to 2015-2016 Citroen offered RNEG/RNEG+ units. They looked all right, but lacked AA/Carplay support. That's when I found the SMEG unit. More specifically, SMEG+IV2. It was offered from 2015 or 2016 I believe, and it has Carplay and Mirrorlink support. Bingo! I ordered the unit with wiring loom and new piano black center piece:

I also had to buy new trim pieces, to house a bigger display:

Now, the fun begins. The quadlock connector needs to be modified, so it can drive the new display. The most important thing: remove pin 15! If you don't you will fry a path on a motherboard of the new unit (ask me how I know...). It is easy to repair (just solder a thin wire where the path was) for someone who has done some SMD soldering and has a microscope, but if you don't, just make sure to disconnect pin 15 before even plugging the unit in. Then, you need to wire the brown connector that goes to the new display:

Then you need to wire the connector for buttons on central console. The are in part B of the quadlock connector. Personally I swapped this part to one from my bought wiring loom, inserted the connections for the microphone and AUX jack and it worked.

Also I had a left-over GPS antenna from the chinese unit, so I repurposed it to work with factory unit using this adapter:

After all that I powered on the unit:

Success! Now I needed to program in the correct VIN (be sure to use v7.57 and select RNEG unit, connect as Citroen C3 A51i model) and now everything works.

I hope this small guide helps anyone that wants to perform this upgrade. I wasn't able to find any decent guide on how to perform this upgrade, so I combined many guides in many languages into one.

Costs

Total cost of parts I needed for this upgrade was about 2000 zł (around $500). It is costly, but for $100 more than the chinese unit I think it's worth it.