Cruise Control drifting slower

psycholist · Apr 18th, 2019, 21:10

Hi All.
Driving up the motorway last week, my 2012 xc70 d5 manual was in cruise, 70 mph in sixth, so revving around 2000.

Very slowly, so that I almost didn’t notice, the car started slowing down though the cruise was still engaged and the dash still said 70. By this point I was doing about 66 / 67. The deceleration was slow enough that my passenger didn’t notice, so nothing like the feeling of disengaging cruise control.

At some point (not sure if it was after pressing the throttle or not) the car accelerated back to 70 and continued normal operation

I don’t have adaptive cruise, so has anyone seen this before?

Thanks in advance.

vcc · Apr 19th, 2019, 21:36

Hi Guys,

I have very similar problem that I notice very often since a month ago on my V70 2012 D3 manual (320.000 km). In that time, I have noticed the following:

- It happens on the highway when cruise control ON at 130 km/h (as I usually drive) and driving uphill.
- The power decreases, velocity starts to decrease, consumption falls to exactly 9.3 l/100km and stays there.
- No light comes on the dash.
- At the beginning, the issue lasted about 10 seconds and after that the car accelerated back and consumption raised back. Now after a month, the issue lasts until the end of the hill. Sometimes it repeats at the next uphill and sometimes does not.
- It never happens if I drive the same hills at higher power/speed and momentarily loose the throttle (due to other slower cars cross my path and I have to brake).
- It never happens on regional roads.
- OBD scanner shows three errors: catalytic temp. sensor, DPF temp. sensor and oxygen sensor.
- Both temp. sensors were changed (because the Volvo mechanic suggested that this is usually the solution) but the problem persists. Also the DPF regen was performed with VIDA to be sure there is not the problem of blocked DPF.

Please suggest what could be the reason. It is not a big problem but it bothers me due to many uphill roads on my daily commute (200 km in both directions). I have a bad feeling because my volvo doesn't perform as it should.

psycholist · Apr 19th, 2019, 22:25

Yes, that sounds pretty much what I get. I don’t have VIDA nearby thought so can’t error check....

Anyone out there with any nuggets of info? Thanks!

Billggski · Apr 20th, 2019, 08:40

My only idea is that if you are in top gear climbing an incline, the engine would be labouring and reduces speed to protect it, returning to cruise control speed when appropriate.?

psycholist · Apr 20th, 2019, 19:34

I had thought this, but had dismissed it, as the revs were still above 2000, so at least the first turbo should’ve been active. I’m used to a rather dim system on a 2000 p2 v70 though which just blundered its way through everything. And I would have thought slower was only going to make things worse?

andyg · Apr 21st, 2019, 11:15

Quote:

Originally Posted by Billggski

My only idea is that if you are in top gear climbing an incline, the engine would be labouring and reduces speed to protect it, returning to cruise control speed when appropriate.?

I think Billiggski might be right. On your next commute try the exact same hill at 70mph but in 5th gear. Hopefully if the cruise control maintains correct speed then I reckon you have proved it is working correctly. The small reduction in speed you experienced last time might just be the engine labouring in top gear, the XC70 being quite a large vehicle? On my S80 auto with cruise control on, the computers will knock it down a gear to maintain speed going up a long incline.

vcc · Apr 21st, 2019, 18:21

It is not the case. I have been driving the same hills with this car for about 200.000 km with the same speed and never experienced this kind of problem before.

Update: I have been searching and found out that someone had similar problem which was solved after replacing MAF.

psycholist · Apr 21st, 2019, 22:58

Any chance you can post a link to that MAF replacement info? I couldn't find anything when I looked. Thanks!

vcc · Apr 22nd, 2019, 07:00

Quote:

Originally Posted by psycholist

Any chance you can post a link to that MAF replacement info? I couldn't find anything when I looked. Thanks!

Here: https://www.volvoforums.org.uk/showt...=280846&page=7

psycholist · Apr 27th, 2019, 18:56

Sorry it took me ages to acknowledge! Appreciate the link.

Apr 18th, 2019, 21:10	#1
psycholist New Member Last Online: Sep 19th, 2023 23:10 Join Date: Sep 2009 Location: Sheffield	Cruise Control drifting slower Hi All. Driving up the motorway last week, my 2012 xc70 d5 manual was in cruise, 70 mph in sixth, so revving around 2000. Very slowly, so that I almost didn’t notice, the car started slowing down though the cruise was still engaged and the dash still said 70. By this point I was doing about 66 / 67. The deceleration was slow enough that my passenger didn’t notice, so nothing like the feeling of disengaging cruise control. At some point (not sure if it was after pressing the throttle or not) the car accelerated back to 70 and continued normal operation I don’t have adaptive cruise, so has anyone seen this before? Thanks in advance.

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Apr 19th, 2019, 21:36	#2
vcc New Member Last Online: Feb 23rd, 2024 09:01 Join Date: Sep 2015 Location: Ljubljana	Hi Guys, I have very similar problem that I notice very often since a month ago on my V70 2012 D3 manual (320.000 km). In that time, I have noticed the following: - It happens on the highway when cruise control ON at 130 km/h (as I usually drive) and driving uphill. - The power decreases, velocity starts to decrease, consumption falls to exactly 9.3 l/100km and stays there. - No light comes on the dash. - At the beginning, the issue lasted about 10 seconds and after that the car accelerated back and consumption raised back. Now after a month, the issue lasts until the end of the hill. Sometimes it repeats at the next uphill and sometimes does not. - It never happens if I drive the same hills at higher power/speed and momentarily loose the throttle (due to other slower cars cross my path and I have to brake). - It never happens on regional roads. - OBD scanner shows three errors: catalytic temp. sensor, DPF temp. sensor and oxygen sensor. - Both temp. sensors were changed (because the Volvo mechanic suggested that this is usually the solution) but the problem persists. Also the DPF regen was performed with VIDA to be sure there is not the problem of blocked DPF. Please suggest what could be the reason. It is not a big problem but it bothers me due to many uphill roads on my daily commute (200 km in both directions). I have a bad feeling because my volvo doesn't perform as it should.

Apr 19th, 2019, 22:25	#3
psycholist New Member Last Online: Sep 19th, 2023 23:10 Join Date: Sep 2009 Location: Sheffield	Yes, that sounds pretty much what I get. I don’t have VIDA nearby thought so can’t error check.... Anyone out there with any nuggets of info? Thanks!

Apr 20th, 2019, 08:40	#4
Billggski Senior Member Last Online: Nov 15th, 2019 13:19 Join Date: Feb 2016 Location: Stone	My only idea is that if you are in top gear climbing an incline, the engine would be labouring and reduces speed to protect it, returning to cruise control speed when appropriate.?

Apr 20th, 2019, 19:34	#5
psycholist New Member Last Online: Sep 19th, 2023 23:10 Join Date: Sep 2009 Location: Sheffield	I had thought this, but had dismissed it, as the revs were still above 2000, so at least the first turbo should’ve been active. I’m used to a rather dim system on a 2000 p2 v70 though which just blundered its way through everything. And I would have thought slower was only going to make things worse?

Apr 21st, 2019, 18:21	#7
vcc New Member Last Online: Feb 23rd, 2024 09:01 Join Date: Sep 2015 Location: Ljubljana	It is not the case. I have been driving the same hills with this car for about 200.000 km with the same speed and never experienced this kind of problem before. Update: I have been searching and found out that someone had similar problem which was solved after replacing MAF.

Apr 21st, 2019, 22:58	#8
psycholist New Member Last Online: Sep 19th, 2023 23:10 Join Date: Sep 2009 Location: Sheffield	Any chance you can post a link to that MAF replacement info? I couldn't find anything when I looked. Thanks!

Apr 27th, 2019, 18:56	#10
psycholist New Member Last Online: Sep 19th, 2023 23:10 Join Date: Sep 2009 Location: Sheffield	Sorry it took me ages to acknowledge! Appreciate the link.

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