Xsara Picasso Cruise Control issue

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MixerFistit
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Xsara Picasso Cruise Control issue

Post by MixerFistit »

I recently installed a replacement display as per viewtopic.php?t=69770.
Afterwards, I noticed when activating my cruise control the odometer and trip counter didn't switch to CC - - - even though cruise control did work correctly.

I was able to activate the feature on Lexia under the instrument panel ecu (changed "missing" to "present").
Cruise control now appears on the display when the stalk switch is rolled.

All good so I thought until I actually attempted to use it on a dual carriageway today.
I was traveling at about 65 mph when I rolled the switch and tapped + to lock in my current speed only to see it select 40. I tapped + again and it jumped to 72, tapped - and it jumped to 146!
+/- buttons then changed the value to completely random values each time including impossible values like 0 and 1 (146 I guess is also pretty much impossible but I mean values below the 25 mph CC lower limit).
It felt like the car was attempting to meet the values the panel displayed (at least the reasonable ones).

Has anyone ever had this issue? Is there another function I need to activate or is the display incompatible with my other equipment? I'm assuming all of the existing configurations were correct as the vehicle came with Cruise control from the factory and the original display worked with CC correctly (before I killed it)
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GiveMeABreak
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Re: Xsara Picasso Cruise Control issue

Post by GiveMeABreak »

You have probably changed a setting that was not meant to be changed or for another vehicle. Please have a read of this advice when using Lexia / Diagbox, otherwise you can cause safety issues with the vehicle:

viewtopic.php?t=60600
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Paul-R
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Re: Xsara Picasso Cruise Control issue

Post by Paul-R »

Setting of CC speed can also be initiated by pressing the - button on both my X7 and our 308. Have you tried that?

Do the + and - buttons work correctly to alter CC speed once it's initiated?
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GiveMeABreak
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Re: Xsara Picasso Cruise Control issue

Post by GiveMeABreak »

He indicates he's doing that in his post unless I'm reading it wrong. The + /- buttons are on the cruise stalk on the Picasso which the X7 does not have and he's getting anomalous speed values when he presses either. This Xsara Picasso uses the separate cruise stalk, nothing else.
MixerFistit
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Re: Xsara Picasso Cruise Control issue

Post by MixerFistit »

Yes that's correct, although I need to amend my claim a touch.

The real speeds are correct and only the display is anomalous. Regardless of the displayed speed it appears as though the +/- correctly set the single and 5 increments.

The CC displays whatever it likes though. I must've for excited when I saw 146 and felt the initial surge of a 5mph step lol
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Re: Xsara Picasso Cruise Control issue

Post by MixerFistit »

Do you think that because the display part number isn't exactly the same it's sending the information in a different format for the display to understand correctly?
Maybe even transmittingat a different baud rate or something.
Would seem odd though as speedometer and mileage figures seem correct so I'd assume everything was standard in that regards.
It's not the end of the world of it can't be resolved, as the speedo will tell the true speed, just annoying.

Maybe for a separate thread but linked to this one, I looked at the replacement parts section in lexia incase there was something I could see in regards to changing the display but the only option is "Petrol Engine" which seems at odds with what I should be seeing on a 1.6 HDi (yes I've put the correct RPO and my VIN is captured correctly).
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GiveMeABreak
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Re: Xsara Picasso Cruise Control issue

Post by GiveMeABreak »

It's because the displays are different for diesel and petrol engines. Yours should be configured already for Diesel, the other is an option for a petrol. Remember the BSI has multiple configuration possibilities and can easily be corrupted if the wrong options are configured - regardless of the VIN. The VIN just picks up all the relevant options for the vehicle as standard for the engine fitted as programmed at the factory. That doesn't stop somebody from altering entries which can basically cause a safety issue or prevent the car from working - as you are finding out.

Incompatibilities between the Switch module / the BSI / the Engine ECU / the Instrument Display ECU can all contribute to issues if they are not compatible, talking to each other or correctly configured.
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Re: Xsara Picasso Cruise Control issue

Post by MixerFistit »

I'm not sure what car this display has come off unfortunately, although the Glow plug bulb was already installed so I'm assuming a diesel but there's also a redundant esp bulb installed and I think even my old display panel had that so not sure if either gives a clue

Oh I just realised there is clearly a section in the LCD where the automatic transmission would display its status so maybe it is off a petrol. Its obviously dark but should it even be there? Do diesels have this redundant section (top left of the speedo's Hundred) even though there were no auto xpic diesels (that I'm aware of)?

That said when my old display was still connected (and already faulty), Lexia would still only show Petrol Engine under replacement parts.
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GiveMeABreak
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Re: Xsara Picasso Cruise Control issue

Post by GiveMeABreak »

Ok, so this is definitely off a petrol if it's got an automatic window display on the instrument panel.

Your issue is going to likely be multiplexing. The vehicle architectures can vary depending on year. Some are VAN only and later models are VAN CAN. The ECUs need to be the same type or the data streams / networks will be sending gibberish.
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Re: Xsara Picasso Cruise Control issue

Post by MixerFistit »

Great stuff, solving the mystery has made the issue less annoying. Maybe useful to someone else if they decide to rejuvenate an old Picasso!
One to look out for next time - how foolish of me to assume the parts would be standard in a citroen :D (I shouldve known already when I removed a non-functioning wing mirror installed by the previous owner and had to transpose the wires from 2 very different connectors - successfully)

All of the other functions seem to be accurate, including fuel and engine temp so I can probably live with it, I might check over the original display to see if I can find any damaged components but I suspect it's corrupted and beyond help
wheeler
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Re: Xsara Picasso Cruise Control issue

Post by wheeler »

MixerFistit wrote:
06 Nov 2021, 20:44
I'm not sure what car this display has come off unfortunately, although the Glow plug bulb was already installed so I'm assuming a diesel but there's also a redundant esp bulb installed and I think even my old display panel had that so not sure if either gives a clue

Oh I just realised there is clearly a section in the LCD where the automatic transmission would display its status so maybe it is off a petrol.
Thats definitely not a good indication of options fitted, Loads of cars may come with all the bulb holders fully populated, doing an actuator test on the panel usually shows them all lit up. The fact it has an auto gearbox display ability on the panel is not a good indicator either. If you look up the parts without VIN filtering there are no gearbox or engine specific options listed, so the same ones were fitted to petrol's, diesels, manual's & automatics.
There are however different options depending on what cruise control & speed limitation options are fitted.
GiveMeABreak wrote:
06 Nov 2021, 23:49
Your issue is going to likely be multiplexing. The vehicle architectures can vary depending on year. Some are VAN only and later models are VAN CAN. The ECUs need to be the same type or the data streams / networks will be sending gibberish.
I'm pretty sure that the VAN & Bi VAN/CAN instrument panels cant be mixed up as the connectors on the back are completely different so should be physically impossible to connect the panel for the wrong type of multiplexing architecture.
VAN/CAN appeared on the Picasso around 2002.
MixerFistit
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Re: Xsara Picasso Cruise Control issue

Post by MixerFistit »

That was my initial assumption I'd seen ones with twin connectors and others with single (like mine).
But then I also wondered why there were so many part numbers for apparently identical units.
As the display was a risky ebay purchase and came with CC display deactivated I suppose there's no guarantee that that area of the display wasn't faulty in the first place with regards to how it communicates with any vehicle not just mine.
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GiveMeABreak
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Re: Xsara Picasso Cruise Control issue

Post by GiveMeABreak »

wheeler wrote:
07 Nov 2021, 14:16
I'm pretty sure that the VAN & Bi VAN/CAN instrument panels cant be mixed up as the connectors on the back are completely different so should be physically impossible to connect the panel for the wrong type of multiplexing architecture.
VAN/CAN appeared on the Picasso around 2002.
That will make it easier to rule out if that's the case - I've only taken a few apart and they were all later diesels.