Hi from Hungary! C5 RT3/RT4 question.

[Alf_theHun]

Hi there,

I own a 2006 3.0i C5 Exclusive since about 5 years now. I have some knowledge on diags and mechanics, so usually I can solve my own problems - however I ran into a very strange issue now, in which noone could help me yet.

Would the admin team be so kind and move my question to the most relevant section of the forum, please?

So, from one day to another, the ambient temperature figures disappeared from the top left of the display of the RT3/RT4 unit (I am still confused about the model, but "screenshot" is attached for your reference).
So I thought - as a common failure - the sensor went out and replaced it...unfortunately this did not help at all.
Should this be something to set up through Lexia? If yes, can you direct me where?

Thanks in advance!

[GiveMeABreak]

Hi

No the sensor, if replaced does not need coding. If the sensor was faulty, you'd probably also have climate control issues as it relies on the outside temp. sensor to determine external ambient temperature for the climate control system.

I suspect in this case it may be a a sign of the head unit or the display starting to fail. As these units are always 'on', try a BSI reset following this guide, it may iron out a temporary glitch.

BSI Reset / Battery Disconnect / Reconnect Procedure

[Alf_theHun]

Hi Marc,

Actually I do have climate control issues, as the passenger side blows cold and the driver side blows hot - I assume due to a broken flap inside the heater box...but this is a different story (are there any good sources for these flaps?)

Anyways, I am sure the sensor is fine as I could see from Lexia that it measures proper values - might have checked that before the replacement - so it is the display which is missing the figures...but the display itself does not look like damaged or malfunctioning. It looks more like the outside temperature display option has been ticked out in the configuration or something - if there is something like that at all.

I will try the BSI reset and will see how it goes - will post the results here.
Thanks!

Alf

[GiveMeABreak]

Your climate issues may be a flap for the air mixing (either plastic gearing has worn on one or both ends of the flap spindle from either flap end or stepper motor end, or the stepper motor itself, or the heater matrix is blocked.

So could be one of three issues.

[Alf_theHun]

It is raining, so I did not want to do the BSI reset at this point, but I did a little bit of investigation.
So the car has a RT3 unit with firmware version 6.63, just checked.
The strange thing is when I start a global test in Lexia, in the listing it shows that the software can not communicate with the Radio and the Multifunction display ECUs.
Then I checked the BSI configuration and there it shows that RT3/RT4 unit is set to not present.
Should I change this to “present” and maybe then I can check the unit configuration as well?

[GiveMeABreak]

I would expect this to be set to present, but experience has told me not to take anything as written when it comes to PSA vehicles.

I’ll have a look at the BSI settings, but be careful not to change anything yet as some options are meant to be set to the opposite of what you would expect, as they may be meant for another model or marque.

I’ll come back when I’ve had a check.

[GiveMeABreak]

Ok, so that's one of the documents I don't have - only the earlier and later one - typical! I suspect you would need to set this to present. My only question is why this was ever disabled - unless there were other issues and a previous owner has perhaps disabled it or somebody else maybe?

Just make a note of any values you change and then you can revert to these if anything goes wrong.

[Hell Razor5543]

This may (or may not) be relevant, but I have experienced something similar on my 2007 C5 VTX+, in that there is no dialogue with either the radio or the multifunction screen (I have an RT4 radio). However, when I told my system (the BSi, I think) that I had a Telematics unit that became visible in the Global Test, and then there were obvious communications (such as the multifunction screen showing a 'Diagnostic' message) when the Telematics was being tested.

[Alf_theHun]

First of all, thanks for the suggestions guys!
Yesterday was my last workday this year, so I could check the car only today.

Spoiler: I finally managed to get the outside temperature displayed again! But it was far from straight forward to say the least…

What I did:

In BSI "Configuration" I set "Presence of telematic unit RT3/RT4" from "No" to "Present" - nothing changed
In BSI "Configuration" I set "Presence of RD4 radio" from "Present" (another weird setting here) to "No" - nothing changed
In BSI "ECUs present" I Set "Telematic" from "Missing" to "Present" - Telematic option appeared under "Global testing"
In Telematic “Configuration" under “Display options” I set "External temperature" from "Inactive" to "Activated" - after hitting “Configure” the system replied “Downloading defective" and unit froze.
Restarted with DARK button, èt voilà! The outside temperature showed up in it’s place!

Strange enough, in the BSI configuration the "Telematic unit RT3/RT4" went back to “No” and "RD4 radio" went back to "Present" by itself….
And with the Radio and Multifunction display there is still no dialogue…

[GiveMeABreak]

It looks like somebody has been there before... Configurations don't change back by themselves and those additional options would make sense - I didn't mention these as I had no reason to suspect they had been altered previously.

I suspect the changes you just made were not actually saved - in other words the parameters were changed but not committed / saved. If you don't telecode them they will revert back to the previous setting.

[Alf_theHun]

I hit "configuration" after each parameter change and it asked for the 5 digit code as well, so I think I did "commit".
Anyways, I am glad that I could find the way…