On my 2017 XE (mfg in late 2016) I have now lost two (2) left window trim moldings. The first one was at about 75-80 MPH and it just flew off the car. Shortly later on the same trip a stone hit the windshield and cracked it. The glass was replaced with the OEM window and both left and right trim molding replaced (required when replacing the windshield). A week later, the left molding flies off at about 60 MPH. This car is hand washed, so its not a car wash damage issue. Anyone else having this? The trim just seems to push on and is not secured. Also the new trims are too long and overlap the body at the top. Easy to snag and pull forward.

What is considered speedometer accuracy for a modern new car? Mine is about 3-4 mph fast at 60 MPH (60 MPH is really 56-57). That is about 7%. Testing is with a GPS numerous times and locations. Seems high in this modern electronics age. Can this be tuned to a be more accurate at freeway speeds? I drive a different rental car about every week and have not found this to be the case in other new cars. They are usually within 1 MPH.

Thanks in advance for any comments!

 

Would complain to Jaguar on the speedometer readings. Should be more accurate. Get a video of the two side by side. JLR Corporate is pretty responsive.

 

The speedometer in my 2017 XE is spot on. Just wondering if you have changed wheels and/or tires which could affect accuracy.

 

Regarding the speedometer reading - In European markets our speedometers are programmed to overread by 3.5% + 2kph (i.e. the actual road speed has 2kph added to it then the result is multiplied by 3.5% to provide the given speedometer reading. The odometer is not affected by the scaling.)

The overread is configured in the vehicle's CCF using two bytes:
Jaguar speedometer calibration - KPH off-set: + 2.0kph (can be 0 or +2.0kph)
Jaguar speedometer calibration - Percentage scaling factor: 3.5% (can be 0, 2.5% or 3.5%)

The spec for US speedometers seems to be up to 10% overread, but I can't find the scaling factor being used:
https://en.wikipedia.org/wiki/Speedometer#International_agreements

The wheel size programmed to the car obviously affects the ECU calculation prior to any scaling.

 

Thanks everyone for the information. I have found JLR to be responsive, but they have not corrected the issues. I was told "nothing is wrong" with the car and all XE are like this (2017 Jaguar XE Diesel with Automatic transmission. I have also been told that Federal Law (US) requires the speedometer to be accurate to 2.5% +- (5% spread). Again. this car is as it came from JLR. No tire, wheel, or other modifications (OK, I did add a Leaper on the hood, perhaps that is causing it).

Attached is a picture of an accurate GPS speed reading with the XE speed reading in the background. Note the card is traveling at 79 and the GPS says 76. The car was on cruise and the GPS had been stable at that speed.

Would others be willing to test their cars and let me know the results? Doesn't have to be the exact year and engine combination.

XE Speedometer says 79, Cars is actually only doing 76. That is over 3% error.

 

I haven't tested the Jag, but your reading (ie +3mph at 79mph) seems about OK judging by the results on previous cars I owned, compared against a Tomtom
Did you get the trim issue fixed?
HTH

 

The US federal standard is 5% + and -, not a spread (so 10% overall). A reported speed of 72-80mph at an actual speed of 76mph is within the US standard.

The UK are stricter - ours cannot under report at any speed.

JLR vehicles can only have their speedometer readings affected by combinations of both of these two settings:
KPH off-set: can be 0 or +2.0kph
Percentage scaling factor: can be 0, 2.5% or 3.5%

None will allow a reduction (subject to error in reading the true speed, which won't be 100% accurate).

In the UK (+2.0kph + 3.5%) a true speed of 76 would be reported as 80mph.

I'm not sure which combination of those two settings is set for NAS vehicles, but all combinations except 0/0 come out as 78 or 79mph for 76mph.

As you cannot drive a vehicle that under reports it speed in the UK and many other regions (even a temporary import) to ensure vehicles can legally be driven across regulatory boundaries car manufactures all adopt very similar adjustments to JLRs. They are a sweet spot that aligns with each set of regulations, which usually works out to +3 to 4mph at 50mph true speed.

 

I was wondering about the speedometer accuracy in our car. Over the summer I notice that it reads around 2-3 mph higher than actual speed out on the highway. This thread answers my question... although I do find it odd.

 

Could you send me a picture of your speed test and you tire/wheel sizes? Thanks.

 

I do not have a pic. Just something I have observed on a couple of occasions when I have been running navigation. I did verify the discrepancy with the GPS in my phone as well.

 

 

In case it wasn't clear it is worth noting that the KPH off-set and Percentage scaling factor can both be reprogrammed on your cars by changing each of those CCF bytes. You could set both to 0 to more closely align the displayed speed with the measured true speed (it is up to you to ensure your vehicle still meets the required regulations for your region).
It is easy to do with SDD + an engineering password (there are ways to do obtain this), and some third party diagnostics tools popular with independent garages can also reprogram the CCF bytes. I think the Autologic one can? A franchised dealer probably wont do it though.

 

xdave, Thanks. I will look into that. May have to drive over to the UK and let you have a go at it.

 

Not a clue on the Spedo, but the Passenger side trim on mine came lose at the top and started started flopping in the wind ~75MPH, I snapped it down and haven't had problems since..