original cruise control not working

[Berlingocamper]

Hi there,

I'm new here and first of all sorry for my English!

I drive a Berlingo (B9, orga number 12049) and have problems with the original built in cruise control. I bought it from private and the cruise control haven't ever worked.

The problem is that most of the time it shows "--" if I try to switch it on so it seems that it doesn't know the current speed. When I drive arround 80 km/h or faster mostly it knows the current speed and sometimes I'm able to switch it on but it switches off again after a few seconds. If I can switch it on and press the accelerator pedal down so that I drive faster than the cruise control is set to it will stay switched on for a while and I can even go off from the accelerator pedal and it holds the current speed for maybe 10 or 15 seconds the it switches off again. If it works for a few seconds I can even increase the speed with the cruise control button, when I stop accelerating it usually switches off again immediately :brickwall:

There are no faults shown in any control units.

I know that's not the engine control (Citroen number 1320) because I replaced it already. I also replaced the switch at the steering wheel and the two sensor wheels on the back (left one was damaged) and the sensor back left side. I cleaned the front sensor wheels. Furthermore I replaced the switch at the clutch pedal and the one on the break pedal. I meassured contacts between PSF, clutch pedal switch and engine control (6783X, KM73X) and between PSF, break pedal switch and engine control (CM21X, 7309X).

I wasn't able to meassure accelerator pedal, it seems that it doesn't contain just simple potentiometers so I have no idea how I can meassure it?

Is there a possibility to investigate what causes the cruise control to switch off again and again? Maybe with Lexia or so?

Thanks a lot for any help!

By the way, the speed limiter and ESP is working fine!

[3rensho]

Grüß Dich aus Basel und willkommen im Forum. Can't offer help with that question since I don't have the Tempomat. Someone will be along shortly I'm sure with advice.

[Berlingocamper]

@3rensho:
Thanks for your warm welcoming :wave:

@all:
Ok, here some new information I learned yesterday:

Meanwhile I assume that the cruise control always knows current speed. If I deactivate it completely then activate int and then switch it on (pressing one of the set buttons) within a second it always shows the current speed! Very short after that, definitely less than one second, it deactivates itself again. This seems to be the time cruise control needs to realizes that something is wrong and it has to switch off itself (e.g. break/clutch pedal pressed or sth. like this).

If I wait for more than one second after activation usually it shows "--". If I drive faster than 80 km/h often it shows the correct speed (4th or 5th gear, never in the lower ones!) so is it possible that is has to do with the gear and/or the revolutions per minute?

Just to be more precise "de-/activate" means cruise control is not shown in the display where "switch off" means it is shown but the word "off" is also shown in the display, "switch on" means it is shown in display and should control the current speed.

If I look at the curcuit diagrams it can be (any suggestions here?):
- break pedal #2120 (meassured and replaced)
- clutch pedal #7306 (meassured and replaced)
- ESP sensors #7810/#7815/#7820/#7825 (all meassured with Bosch tester and one replaced)
- EPS sensor wheels (all cleaned, back ones replaced)
- engine control unit #1320 (replaced and connections to pedals meassured)
- switch at the steering wheel #CV00 (replaced)
- central control unit #BSI1 (not yet touched)
- fuse box #PSF1 (not yet touched but fuses are ok)
- speed meter unit #0004 (not yet touched)
- ESP control unit #7800 (not yet touched)
- G-Sensor #7804 (not yet touched)
- injection anything #12-- (don't know exactly what "#12--" can be because there are 100 possibilities, therefore, not yet touched)

Little bit newer Berlingos than mine got a resistor between 12V and the break pedal (#2102) can this cause my problem?

By the way, ESP and ABS is working fine...

[Berlingocamper]

Replaced gas pedal, no success.

Replaced one front ABS sensor and a rear one, no success. Replaced the others with the removed ones, no success.

Thanks a lot for any further suggestions.

[dumdum]

Stop spending money like water?? That's a good suggestion! Cruise is simple, if abs works ok ten checking abs sensors and the like is pointless, cruise gets a lot of info from it so if the abs works all the abs parts are ok

Gas pedal has no influence over cruise if engine management light isn't on

You need a peugeot planet plugging in and reading codes from a global test to see why cruise drops out, could be as simple as a brake pedal switch...

Or you could carry on guessing and spend lots of money and waste your time trying to fix parts that aren't broken... Sorry if I'm blunt but trying to fix cruise with very little knowledge of how it functions is like me trying to guess what size inside leg you have from my iphone sat here now

[Berlingocamper]

Hii dumdum,

thanks a lot for your answer.

Back from paragliding holiday, I have time again to be spent on that (2000km without cruise control is not really funny )

First of all you are absolutely right, "spending money like water" wasn't the plan but most of the more expensive parts have been replaced by my official workshop and they for sure have a "peugeot planet", I hope you see the real problem After spending a lot of money there I started analyzing the problem by myself...

Meanwhile my own "peugeot planet" with typical software has been arrived, I have no experience with it but this should be just a matter of time.

The next days I will play arround with diagbox and Lexia but any help how to analyze my cruise control problem with mentioned software is very welcome!

[dumdum]

start by doing a global test of all systems and see what comes up, brake or clutch switch faults are favourite... but any engine management fault will kill cruise, even if its intermittent... report back

[Berlingocamper]

Meanwhile my car scanner arrived and I found time to play arround with L*xia a bit.

I couldn't find any stored faults so this looks fine so far.

Not nice is that L*xia stops watching ESP values at a speed of 10km/h

This are my current results (language of my L*xia is not english so I hope my translations are understandable):

BSI:
connecting pins 1+2 of break switch = BSI shows break pedal is beeing pressed
connection pins 3+4 of break switch = no BSI reaction

ECU (EDC16C3):
"break pedal main switch" (L*exia says this comes from BSI) works if I connect pins 1+2 of break switch
"beak pedal secondary switch" works if I connect pins 3+4 of break switch
clutch works

ESP:
"break contact" works if I connect pins 1+2 of break pedal
connecting pins 3+4 leads to no reaction here...
"secondary break light contact switch" (L*exia says this is used for cruise control) is always shown as pressed <-- seems to be a hot candidate!

All signals are seen from the control unit they are directly connected to. But it seems that ESP only gets break pedal information from BSI but not from ECU. On the other side CAN communication should work, otherwise I think I would see some errors.

So the question is: Is the information not send by ECU or is it not received by the ESP?

Thanks a lot for any suggestions.


Btw. because of the results above I did some more analyzation with the ECU:

• - no jumper between 1+2 and 3+4 means primary and secondary switch pressed
  
• - jumper between 1+2 but not between 3+4 means the same
  
• - jumper between 3+4 but not between 1+2 means primary and secondary switch NOT pressed
  
• - jumper between 1+2 and 3+4 means primary switch pressed, secondary switch not pressed.
  

[Trevor]

Modern car electrics are beyond me but I do agree that your' "secondary break light contact switch" (L*exia says this is used for cruise control) is always shown as pressed <-- seems to be a hot candidate!
If it thinks this is open it would not engage.

[Berlingocamper]

ok, some more strange experiences today...

Diagnosis from yesterday have been made with lexia v7.11.

Today I used Lexia v7.24 and deactivated cruise control and activated it again. Cruise control is still not working but now the limiter is gone, too. If I switch it on it doesn't work and it's even not shown in the display (cruise control is still shown). It seems that v7.24 can only activate cruise control but not the Limiter?!? Tried to do the same with v7.11 but there exists no "cruise control enable/disable" option to be chosen.

Any idea what can be the reason for this and how I can get at least my limiter back?

Is it possible that the cruise control was not originaly installed and one of the two previous owners tried to install it and all that worked was the limiter?

Is it worth installing an old lexia v5.xx version to get the limiter back working?

Another crazy thing is that v7.11 says my ESP control unit is an ESP8.1 one but v7.24 says it's unknown, huh what's going on here? If Lexia is really that buggy it's no wonder why my local workshop cannot localize the error

Meanwhile I think best way is to deactivate this damned piece of hardware and buy an universal one from Waeco

Thanks for any advice!

Btw. does anybody know a good and cheap CAN bus sniffer? Tried my ELM327 today but after a few messages it tells me that its buffer is full... /EDIT: ok, I realized that ELM supports baud rates up to 500kbps, I will try this tomorrow and hope this will fix my buffer full problem.