Cruise control problem 850-95

chrillew · Post by **chrillew** » 20 Oct 2018, 09:01

Hey

I have a problem i swapped everything out regarding the cruise control. speeds below 90kmh pressing + for increasing speed seems sluggish, nothing really happends. but above 90kmh it works as intended it holds the speed perfect and is responding to inputs.

But below that speed increasing or engaging the cruise control is a hit or a miss.

Not sure what it might be

Post by **Ozark Lee** » 22 Oct 2018, 08:18

The manual has an entire procedure for diagnosing and repairing cruise control problems.

https://www.matthewsvolvosite.com/downlo ... vo_850.zip

After you unzip it see the file named "cruise control system.pdf" and there will be step by step procedures.

...Lee

Post by **misha** » 23 Oct 2018, 04:56

Cruise control will not work below 80km/h....if i remember correctly.

Post by **abscate** » 23 Oct 2018, 06:34

50 km/hr is the cutoff in the states , is it different in EU markets?

That’s probably a speed sensor input to the cruise module, I wonder if that points to the problem here?

chrillew · Post by **chrillew** » 24 Oct 2018, 11:01

Thanks ive read up on the diagnosis but cant find anything relevant, or im blind.

Yea below 90km/h its very hard to engage cruise control and usually pressing + makes it go slower especially around 70km/h.

Above 90km/h it seems normal, or what i belive is normal. when pressing + it does increase speed and holds it uphill and on straights fine. But something that i noticed is when i last tried then resume function didnt seem to work at all.

Speed sensor input hm ill read on that.

Post by **misha** » 24 Oct 2018, 13:04

Could be that you have a problem with contacts in the handle.

Sommerfeldt · Post by **Sommerfeldt** » 26 Oct 2018, 03:51

Cruise control works fine down to 50 km/h on my '96.

Check the vacuum pump for the CC, under the battery tray and that the hoses to/from it are connected correctly, and that the blind one is plugged. On my previous 850, the switch failed and made it go a little haywire when increasing/decreasing speed, so that's also a good tip from misha.

The servo controlling the throttle is also very susceptible to wear - also check connections there.

- S

Post by **rspi** » 28 Oct 2018, 12:24

Post by **rspi** » 28 Oct 2018, 12:24

If you have ABS issues it can knock out the cruise.

Also, I once had cruise issues that ended up being a bad wire going into the top of my cluster. Took me weeks to find that.

chrillew · Post by **chrillew** » 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?