Cruise control problem 850-95

Post by **rspi** » 12 Nov 2018, 09:41

chrillew wrote: 30 Oct 2018, 08:57 I have replaced the the vacuum pump from a newer v70 i think it was, so only 1 connection to plug in if i remember. and multiple relays. i think the tubing is correct tho since it works ok on higher speeds.
Gonna check if everything is ok by the pedals but i think it was the last time i looked.

Getting a feel it could be the either the switches or something with the signal wire your talking about. but my odo meter is just working fine, but there is a wire going from the cluster to the relay?

Something stops it from working under 25 mph. Maybe that is bad and things 50 is the new 25.

chrillew · Post by **chrillew** » 28 Nov 2018, 06:57

Ive done some more testing now, now it doesnt seem to work on the + function. and resume doesnt do a thing.
when i press + i feel a small touch on the gas pedal like it wants to do something but nothing else.

The cruise control seems to work like this now. if i speed up to any speed. lets say 70km/h and press" - "it engages the Cruise but lowers the speed to around 65ish but its holding the speed on hills and such(like normal). this applies to almost any speed ive tested recently.

So maybe its just the switch thats bad? ive checked the loom from the steering column to switch 2 years ago last time i went diagnosing and didnt find any visual suspect.

Post by **abscate** » 28 Nov 2018, 07:34

Thats indicative of a vacuum problem not holding the throttle at the right place. I thought the feedback was via speed sensor but don't know that system well.

On ETM, its a simple piece of software and no hardware. Yeah

(shameless boast called out by moderator)

chrillew · Post by **chrillew** » 28 Nov 2018, 07:45

U think its the vacuum ? i mean if i press " -" button it activates the cruise but lowers the speed first some kmh, like i think its supposed to since its - not +. could be wrong.

And when i've pressed the - button it will hold that speed fine( but lowers initial speed at first around 5km/h) i feel the pedal adjusting and depressing in large hills. the speed rarely dips when its been engaged.

I hope this clarifies it. Since it seem to hold the speed and adjusting the pedal according to hills etc i think its the switch thats mocking me up using the other functions.

Post by **abscate** » 28 Nov 2018, 09:16

The +- buttons should both just lock in the current speed, no difference in function according to user manual.The fact the speed drifts means something isnt right in the system manipulating the throttle - I would give 20:1 odds its a mechanical vs electronic failure.

Post by **erikv11** » 28 Nov 2018, 09:19

Look at the very first reply, from Lee. The troubleshooting guide has clear, step by step instructions how to bypass the switch and test the pump and vacuum lines, with the car sitting in the driveway.

Have any of the rubber vacuum lines ever been replaced?

chrillew · Post by **chrillew** » 28 Nov 2018, 09:37

Okey thanks! ill do some vacuum testing, no hoses or Rubber elbows for The Cruise has been replaced, so i see your point now.

Might it be that simple