Cruise control not working in 5th gear

[Silentbob90]

Just retrofitted cruise control and all working fine in 4th gear. 
Shift to 5th gear and it just flashes and wont engage. 

Anyone any idea what this could be?

[Trevor]

So what happens if you don’t engage it until your in 5th? Does it engage then?

[Silentbob90]

So what happens if you don’t engage it until your in 5th? Does it engage then?

No wont engage in 5th at all.

Thought it wasnt working at first only tried in 5th gear thought speed might not be fast enough so tried on motorway at 70mph still nothing.

On my way home through town was pressing the buttons and it engaged in 4th.

In 1st 2nd and third if i try enable Cruise control i get a message on info screen saying "CRUISE CONTROL IMPOSSIBLE"

In 4th no message, and 5th I get no info message either so van must know cruise control is possible.
I noticed if I try to enable cruise control immediatly after shifting it enables for 1 second and then goess to off. If i wait nothing happens speed just flashes

I have done a full scan but no faults present.

[Trevor]

From what I can discover CC will only work in 4th and 5th gear and it will operate above 30MPH, well it does on mine.
Is your clutch switch working ok?
Apart from that I am afraid that I can be of no more help

[cancunia]

Can you test via Lexia / Diagbox what gear the ECU thinks you're in?

[saskak]

Not quite the same, but my CC sometimes and in a completely random fashion just switches off while driving in 5th on a motorway (65-70mph). I have yet to understand why it does that. Your fault seems way more severe though.
As Trevor and cancunia mentioned, check the brake and clutch switches and see selected gear in Lexia/Diagbox.

[Silentbob90]

From what I can discover CC will only work in 4th and 5th gear and it will operate above 30MPH, well it does on mine.
Is your clutch switch working ok?
Apart from that I am afraid that I can be of no more help

I presume the clutch switch is working. it has to be if its working in 4th. touching the clutch disengages cruise.


How can i check what gear the ECU is in in diag box. I enabled CC with a launch tool but have access to diagbox if i need it.

[cancunia]

How can i check what gear the ECU is in in diag box. I enabled CC with a launch tool but have access to diagbox if i need it.

Pardon my ignorance, what's a 'launch tool'?
There are various actuator tests in Lexia / Diagbox but I don't recall exactly where / how you can check what gear is selected. One thing that I'd try with Diagbox is to remove and re-install the CC. There are a few instructions on here about how to do that.

[Silentbob90]

How can i check what gear the ECU is in in diag box. I enabled CC with a launch tool but have access to diagbox if i need it.

Pardon my ignorance, what's a 'launch tool'?
There are various actuator tests in Lexia / Diagbox but I don't recall exactly where / how you can check what gear is selected. One thing that I'd try with Diagbox is to remove and re-install the CC. There are a few instructions on here about how to do that.

LAUNCH is the brand name they are just a generic obd tool that work on nearly all different brands. Think the model was a x431.

Will get diagbox and see if that makes a difference.

[Silentbob90]

OK undid everything i done with LAUNCH and reconfigured using DIAGBOX still no change.

Was able to see data for selected gear and sure enough when I shift to 5th, the stream changes to 5th for a split second and then to NEUTRAL.

What could be causing the ecu to think its in NEUTRAL when its actually in 5th gear?