We have had the car since July 2021 and are generally very happy.
Most driving is local within the ~35Km electric range, so only 4 tankfuls of petrol so far.
But while driving on electric only in Hybrid mode, confirmed by TA trip meter showing 0.0l/100Km, the petrol gauge often changes - down, as if petrol used, and up - recreated!?
Lots of small variations, but some 4-8l. Range to empty on petrol changes approximately to match.
So we have little confidence in it.
At a post-purchase checkup, the dealers declared "sensors checked - normal". They seem unwilling to recognise that detailed records I've taken of the variations are showing a real problem.
They have roughly described an inverted U shaped tank with sensors in each side, and a (slow) cross-flow pump - is this accurate?
They also suggested low resolution of the sensors leading to stepping from one reading to the next. But my observed 4-8l - 1-2 full steps of the 12-step gauge would be horribly coarse.
They suggested cornering forces - but I don't do repeated violent corners all in one direction.
In any case, simple averaging of the two sensors should give the correct value.

Does anyone have any similar experience, or ideas why this may be happening?
I thought accurate petrol gauge technology was simple, old stuff - I've never seen such poor and erratic performance on other cars.

John

 

Update:
No responses - am I the unlucky only one with this problem?
But I can add:

Dealers had nothing to offer, and have still not confirmed tank/sensor details.
Their only hope was a software update scheduled for Feb 22.
This was finally done in April.
And I'm hopeful!
On our first long road trip in May (Brisbane – Sydney – Brisbane) it showed steady and predictable consumption running on petrol engine all the time.
Since returning, we are still only 2/12 of the gauge used, including some Power mode to provoke it, and there is not the regular random up and down we saw in the past.
We did have one gain of 2.5l while parked in Sydney on a slope down and to the left, lost again next morning after driving away. I still don't see why a properly designed gauge should do this ...

 

Months later, and neither local dealer nor Volvo Australia can offer any explanation.

We have confirmed from two sources that the petrol tank is *not* an inverted U.
It's more an L shape with the long arm across the top and the short arm down one side.
So fuel should drain naturally to the low side, where gauge and sender are located.

But we still get variations down and *up* when no petrol is being used, and readings are taken when parked on a level surface.
Very disappointing - how hard is a petrol gauge?

 

I posted a similar question last summer and never got much of a response so let me at least respond to yours so you don’t feel lonely! Although I have no explanation. More to just share being perplexed. Our 2022 XC60 Recharge ER was showing 480 miles to empty for weeks during which we only used electric (I doubt that was very accurate but that’s what it showed). Then for no reason within about one week’s time (of still starting and driving only in electric) it dropped to around 390 miles to empty. I asked my service manager what would cause that. He said something about tire rotation being his guess, which makes no sense, but admitted he really didn’t know. Another technological issue with an otherwise wonderfully driving vehicle. I’ve had several technological “issues” which haven’t made me a totally happy camper with our purchase. As a more minor issue, it annoys me that distance to empty increases or drops in 10 mile increments versus by individual mile. I’ve never seen that before and it’s something I’d never have expected. Don’t know if it’s a Volvo thing as this one’s our first, and probably our last.

 

Second try - I think it lost my first ...

Thanks for your response chg1951.
But I think your problem is range to empty, not petrol gauge reading.
The range to empty should be calculated from fuel left and driving style. For a given amount of fuel, the range will be greater for more efficient highway driving,
and less for city driving when stops and starts mean fuel is used to accelerate the car only for that kinetic energy to be lost as brake heat at the next traffic light or slow down.
(The opposite to electric driving, when those city stops use regeneration to put it back in the battery.)

Over a period of the same style of driving, with no petrol use (like our last 2 weeks), the petrol level would remain the same, and so would the range to empty.
Our range to empty is varying, but only because it's tracking the mad variations of the petrol gauge.
According to the gauge, we lose up to 5l on a fully-electric trip, only to get it back the next day!
Petrol gauge technology is not exactly rocket science - all our other cars have managed to get it right.

We too have other ****les. For example, cruise control speed setting changing in steps of 5km/h, which makes it hard to set the exact speed limit, when the speedo (by design) indicates 2km/h over real speed.
Our previous Ford stepped 1km/h, or if you held the button by 10km/h. Simple, flexible - good design.

But we are very happy with the XC40 - lovely car to drive, 360-degree camera is magic, hybrid suits our use perfectly.
It's just frustrating that both dealer and national customer care will not admit there is a problem, even when presented with masses of careful recordings of the crazy gauge readings.

 

I have experienced these issues too so you are not alone.

 

Experiencing same thing in my 2022 XC90 recharge. Check engine light also on and off on long petrol drives. After a complete fill up, the gauge does not go to complete full, gauge shows 9/10 full. I thought it was maybe the pump stopping prematurely but not the case since I filled up until petro over spilled. Also experiencing around half full, gauge again will fluctuate between 1/4 to 1/2 going back and forth. Obviously something wrong with the sensor. Bringing in for 10k mile maintenance in 2 weeks for a number of issues explained above and also our A/C unit only blows low or high, no in between. Too many tech issues for an expensive car.

 

Wow Sbyrd you have more problems than me:
No Check engine lights
Complete fill => gauge shows 12/12. (1)
Fluctuations - yes! - and maybe more at midrange. (2)
A/c fine.

Further notes:
(1) My comparison of amount of fuel put in to complete full so that filler cutoff releases vs gauge strongly suggested:
There is about 2.4l above 12/12 on the gauge - above the sensor + filler neck?
There is about 2,4l below 0/12 - Volvo protecting us silly drivers from ourselves?
(2) I've been sitting around 1/4 full for quite a while now (our usage is almost all around town within electric range), and the gauge has has only minor fluctuations.
I'm waiting for next fill to see if the real craziness sets in at higher levels.
[Aside: These days I only add a half tank. With petrol needed only every 2 or 3 months for a half tank, this is to avoid stale petrol - though I'm also told this is not such a problem with premium petrol (RON 98).]

So, I'm holding off till next petrol addition. If the craziness returns, I'll also request a sensor replacement under warranty, as neither dealer nor national Volvo have come up with any other explanation.

John

 

Just got home from a 300 mile ride. While check engine was on last 3 days including earlier today, it decided to turn off again magically when starting car before drive. Filled up and have a quarter tank left. Yes I have noticed it does
stay on quarter tank for quite a while. For US, last time I filled up, after pump auto stopped, I filled an additional ~.4 gallons before overspill occurred. Currently at 12k miles.

 

I'm guessing from the miles & gallons that you are in the USA?
You mention 0.4gallons = 1.8l from pump auto stop to overspill;
I just do a brief extra bit after auto off in case it was false - typically cuts off again immediately. Never get to overspill.
On our only long trip - Brisbane to Sydney - we got about 650km on petrol from gauge=12/12 down to 2/12. So we got better than your 300 miles on 3/4 tank = 480km on 9/12. Brisbane-Sydney is almost all modern divided road (freeway), so economical cruising at a steady 110km/h.

We are at 12300km.

John