P38A Cruise control not working

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300bhp/ton

Well-Known Member
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4,733
Location
Near MK
Any ideas? Is there something common.

Hasn't worked since I started having ABS issues, but no error codes showing. Cruise button works and lights up, but nothing happens when you press the Set button on the steering wheel.
 
Replaced all mine but it still won't play "Cruise" properly.
Funnily though if I'm on a flat road at 50-55 it will "sort of" work and I can feel the throttle pedal pull out from under my foot.
But any other speed/load and it just fails to hold. I have changed the ECU, the little power supply unit and the pedal switch.
I reckon the vac unit has no guts. :(
 
Replaced all mine but it still won't play "Cruise" properly.
Funnily though if I'm on a flat road at 50-55 it will "sort of" work and I can feel the throttle pedal pull out from under my foot.
But any other speed/load and it just fails to hold. I have changed the ECU, the little power supply unit and the pedal switch.
I reckon the vac unit has no guts. :(
Check you put the cruise switch back in with the pipe on top side as it effects the seating on the switch.

I found out the hard way. The only way I could get it to work was to lift the brake pedal with my foot until I put it back in the right direction.
 
Any ideas? Is there something common.

Hasn't worked since I started having ABS issues, but no error codes showing. Cruise button works and lights up, but nothing happens when you press the Set button on the steering wheel.
Can you hear the relay clicking when you press the reset/right side on wheel, Does it work when driving if you lift brake pedal while driving?
 
Replaced all mine but it still won't play "Cruise" properly.
Funnily though if I'm on a flat road at 50-55 it will "sort of" work and I can feel the throttle pedal pull out from under my foot.
But any other speed/load and it just fails to hold. I have changed the ECU, the little power supply unit and the pedal switch.
I reckon the vac unit has no guts. :(
You can check the bellows haven't gained a hole, pull the pipe off, push the mechanism all the way in then put your finger over the pipe, should stay in and not release. If it does then you have a leak
 
Mine had a perished pipe in a number of places and the switch at the pedal end had come adrift. Fitted a new reinforced pipe from a local firm who do gas, air and hydraulics.
 
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