Auris Hybrid cruise control intermittent failure to increase speed by single click

[awarberg]

I have an intermittent failure of the cruise control to increase speed in response to a single click up. This sometimes work and sometimes I need to give up after multiple clicks and use the speeder instead (or hold the cruise control arm up, which always works) to get the necessary speed.

I asked my dealership about this and they don't know about this type of problem (at least for newer cars, mine is from 2018). We tried to reproduce the problem but was not failing at the time. (They suggested there is no such feature to gradually increase the speed by single click, but it does work sometimes, and is clearly stated in the manual as well.)

When the fault occurs I click up the cruise control arm and notice that the engine does not rev up and the speed is unchanged even after waiting 5-10 seconds and clicking up multiple times. I have not noticed the fault to correlate with any particular speed and the road is usually flat. Clicking down to reduce speed always works.

Did any of you experience something similar? How can I convince my dealer to take a serious look into bad wiring, software issues, etc. given that I can't reliably reproduce the issue during a 5 minute drive and there are no error codes emitted?

Thank you,
Andreas

[FROSTYBALLS]

An extract from the UK owners manual shows that moving the stalk up of down momentarily - presumably one click - increases or decreases the speed by only 1mph (1.6kph). I would have though that such a minor adjustment would not have much of an effect on engine revs, etc.

To change the set speed, operate the lever until the desired set speed is obtained.

Fine adjustment: Momentarily move the lever in the desired direction. Large adjustment: Hold the lever in the desired direction.

The set speed will be increased or decreased as follows:

Fine adjustment: By approximately 1.6 km/h (1 mph) each time the lever is operated.

Large adjustment: The set speed can be increased or decreased continually until the lever is released.

 

[Mike J.]

3 hours ago, awarberg said:

I have an intermittent failure of the cruise control to increase speed in response to a single click up. This sometimes work and sometimes I need to give up after multiple clicks and use the speeder instead (or hold the cruise control arm up, which always works) to get the necessary speed.

Did any of you experience something similar? 

Yes, this happens at random with my 2013 Yaris Hybrid. A long hold upward cures it as you mention. In my opinion it is of not worth worrying about, but if you find a cure it will probably be a software upgrade, so keep in touch.

[eygo]

the answer listed by mike Large adjustment: The set speed can be increased or decreased continually until the lever is released.

it does take quite a few seconds before you notice the increase / decease in speed

[Mike J.]

6 minutes ago, eygo said:

the answer listed by mike Large adjustment: The set speed can be increased or decreased continually until the lever is released.

it does take quite a few seconds before you notice the increase / decease in speed

Nope, we are talking about the random failure of the fine adjustment when increasing speeds. IIRC, it is after a resume only and randomly. Perhaps the software activated a resume, but forgot to set a flag that it resumed?

[awarberg]

3 hours ago, FROSTYBALLS said:

An extract from the UK owners manual shows that moving the stalk up of down momentarily - presumably one click - increases or decreases the speed by only 1mph (1.6kph). I would have though that such a minor adjustment would not have much of an effect on engine revs, etc.

To change the set speed, operate the lever until the desired set speed is obtained.

Fine adjustment: Momentarily move the lever in the desired direction. Large adjustment: Hold the lever in the desired direction.

The set speed will be increased or decreased as follows:

Fine adjustment: By approximately 1.6 km/h (1 mph) each time the lever is operated.

Large adjustment: The set speed can be increased or decreased continually until the lever is released.

 

The fine adjustment is audible and can easily bring the hybrid vehicle out of EV mode and cause the engine to come on.

In any case, the desired speed increase is lacking when this fault occurs, which is my point.

[awarberg]

20 minutes ago, Mike J. said:

Nope, we are talking about the random failure of the fine adjustment when increasing speeds. IIRC, it is after a resume only and randomly. Perhaps the software activated a resume, but forgot to set a flag that it resumed?

Good info. I will test if the fault is more reliably reproducible after using resume.

I agree it is a small nuisance, but annoying, especially in a Toyota vehicle, considering the reputation for reliability (and the price premium that follows).

[FROSTYBALLS]

56 minutes ago, awarberg said:

and the price premium that follows).

Disagree about the price premium. In the UK, the sixth largest car market globally, the majority of Toyota products are competitively priced against the opposition. The list prices compare favourably with other manufacturers - Ford, PSA including Vauxhall, VW, Hyundai, Kia, Mazda, etc. Yes some manufacturers offer larger discounts, but that has always been the case, and Toyota are more interested in being profitable, rather than producing volumes.at the expense of profits.