Cruise control issues - 308 T7

[nedim0702]

Hi!

I am having an issue with my cruise control and I was hoping for some guidance how to tackle it.

The issue presents itself after a hard acceleration, for example, getting up to highway speeds, after which the cruise control starts blinking and cannot be activated anymore.
It’s only able to be activated again after the car has been turned off and on again, but the issue reappears again when stepping on the pedal.
Note that during driving on city speeds, cruise works fine (if there is no erratic acceleration).

Lexia is showing no errors, nor any error lights are on. Car is running fine, without any noticeable changes in driving behavior.

What I’ve tried so far is changing the break switch, and changing the vacuum doser (the old one broke apart), but the issue is still present.

Would love some guidance on how to diagnose the issue and fixing it.

Thanks!

[GiveMeABreak]

My first thought would of been the brake pedal switch, but you have already done this.

There are certain engine management system or ABS / ESP faults that will disable speed limiter and cruise control functions, but if you are not showing any faults, can you confirm under a global diagnostic test that your diagnostic kit can read the ESP / ABS ECU? If not this may be one reason why you're not getting a fault code. The other reason is that it may be an intermittent fault. You should be able to go into the fault log history and see a list of faults when they occurred.

[nedim0702]

Thanks Marc.
Forgot to note that the speed limiter is working without any issues, it’s just the cruise control.

I don't have Lexia myself, the mechanic ran the diagnostics and said that he found no issues. I was present and can confirm that I saw no faults when he ran the scan, however I am not sure if he went into the history log.

Is there any diagnosis that can be done without the scan tool to determine the issue, or is it my best bet to try and get a detailed history log with the Lexia/Diag box?

[GiveMeABreak]

No, sorry, you'll need Diagbox / PP2000 to read the historical logs.