Can anyone tell me if this is the speed sensor?

This is the Forum for all your Citroen Technical Questions, Problems or Advice.

Moderator: RichardW

Post Reply
Blazer811
Posts: 44
Joined: 25 Nov 2019, 12:51
Location: Perth Western Australia
My Cars: 2004 Citroen VU Berlingo 1.4i (M59)
x 1

Can anyone tell me if this is the speed sensor?

Post by Blazer811 »

Hi all,Hi all, I have a 2004 Berlingo 1.4i van and the speedo shows around 10kmh more than what I am actually doing. I have searched high and low for the speed sensor unit and this is the only thing that I’m thinking it could possibly be.

If it isn’t, can someone please point me in the right direction.

Many thanks
F482D4CB-80EB-4B8C-BC18-19FA6F9881CB.jpeg
User avatar
white exec
Moderating Team
Posts: 7445
Joined: 21 Dec 2015, 12:46
Location: Sayalonga, Malaga, Spain
My Cars: 1996 XM 2.5TD Exclusive hatch RHD
1992 BX19D Millesime hatch LHD
previously 1989 BX19RD, 1998 ZX 1.9D auto, 2001 Xantia 1.8i auto
and lots of Rovers before that: 1935 Ten, 1947 Sixteen, 1960 P5 3-litre, 1966 P6 2000, 1972 P6 2000TC, and 1975 P6B 3500S
x 1752

Re: Can anyone tell me if this is the speed sensor?

Post by white exec »

That's it.
The instrument is just a voltmeter, so possible that it is over-reading. If the reading is steady and consistent, it could even be just a matter of realigning the pointer - a delicate job, usually.
Someone here may have come across the fault before. Do post your VIN, which could help.
Chris
Blazer811
Posts: 44
Joined: 25 Nov 2019, 12:51
Location: Perth Western Australia
My Cars: 2004 Citroen VU Berlingo 1.4i (M59)
x 1

Re: Can anyone tell me if this is the speed sensor?

Post by Blazer811 »

white exec wrote: 08 Feb 2020, 07:21 That's it.
The instrument is just a voltmeter, so possible that it is over-reading. If the reading is steady and consistent, it could even be just a matter of realigning the pointer - a delicate job, usually.
Someone here may have come across the fault before. Do post your VIN, which could help.
Thanks Chris, my VIN is VF7**************[VIN obfuscated, can be read by forum staff]. I have also just read an interesting article which states “ European law (ECE-R39) says speedometers cannot show speeds less than the actual speed, and they must never show more than the 110 per cent of actual speed plus 4 km/h. So, under those rules, a car could be moving at 100 km/h, but the speedometer could legally display as high as 114 km/h”.

So I’m wondering if the speedo is actually working? I know that when I’m doing 100kmh my speedo is showing around the 114 km/h mark.

If this is the case is then my speedo might be calibrated to that law and if so, is there any way I can calibrate it accordingly to reflect the correct speed of travel?

I’ve also noticed that my speedo doesn’t have a starting point of 0 km/h and starts from 10 km/h, is this how they were manufactured or is my pointer thats out of whack?
4F4F99A4-826F-4FF9-8653-52BFEDE1C3EB.png
furriegurrie
Posts: 150
Joined: 07 Dec 2012, 15:21
Location:
My Cars:
x 22

Re: Can anyone tell me if this is the speed sensor?

Post by furriegurrie »

Do you have the correct tires fitted to the car? Different size than factory spec will also influence the speed indicated vs actual speed.
User avatar
Huskyxantia
Donor 2023
Posts: 1939
Joined: 30 Jul 2018, 22:11
Location: Surrey Kent sussex border
My Cars: Past cars
Xsara Picasso 2019 to 2022 r.i.p
Xantia mk1&2 1.9D & 2.0Hdi
Peugeot 206 sw 1.4hdi
Other models
Skoda fabia,escort van,ford ka,Vauxhall astra g car & estate, Vauxhall corsa b, Suzuki swift
Escorts mk 1,2,3,4,5 fiestas mk 1,2, Sierra diesel mk1 Mondeo mk1 diesel .
Peugeot 207 , 307sw

Now cars
Picasso 2.0Hdi now gone to scrappie
Citroen zx estate 1.9D the cherished one
Peugeot 206cc raised from the dead & saved from the crusher traded up to a 308cc
307sw traded for the 207 .

Wish list.
Peugeot 405 diesel
106 or 206
Mondeo Mk1 diesel once owned 1.8tdi was real nice.
x 395

Re: Can anyone tell me if this is the speed sensor?

Post by Huskyxantia »

Blazer811 wrote: 08 Feb 2020, 05:14 Hi all,Hi all, I have a 2004 Berlingo 1.4i van and the speedo shows around 10kmh more than what I am actually doing. I have searched high and low for the speed sensor unit and this is the only thing that I’m thinking it could possibly be.

If it isn’t, can someone please point me in the right direction.

Many thanks
Image
Sure is
Husky. :?
User avatar
Huskyxantia
Donor 2023
Posts: 1939
Joined: 30 Jul 2018, 22:11
Location: Surrey Kent sussex border
My Cars: Past cars
Xsara Picasso 2019 to 2022 r.i.p
Xantia mk1&2 1.9D & 2.0Hdi
Peugeot 206 sw 1.4hdi
Other models
Skoda fabia,escort van,ford ka,Vauxhall astra g car & estate, Vauxhall corsa b, Suzuki swift
Escorts mk 1,2,3,4,5 fiestas mk 1,2, Sierra diesel mk1 Mondeo mk1 diesel .
Peugeot 207 , 307sw

Now cars
Picasso 2.0Hdi now gone to scrappie
Citroen zx estate 1.9D the cherished one
Peugeot 206cc raised from the dead & saved from the crusher traded up to a 308cc
307sw traded for the 207 .

Wish list.
Peugeot 405 diesel
106 or 206
Mondeo Mk1 diesel once owned 1.8tdi was real nice.
x 395

Re: Can anyone tell me if this is the speed sensor?

Post by Huskyxantia »

furriegurrie wrote: 08 Feb 2020, 08:02 Do you have the correct tires fitted to the car? Different size than factory spec will also influence the speed indicated vs actual speed.
If the gear box is the same but a differnt model then the sensor will be the same wheel size can make a difference to speed smaller wheels make needle lift quicker and vice versa , that's my experience a few years back, if it makes sence
Husky. :?
User avatar
white exec
Moderating Team
Posts: 7445
Joined: 21 Dec 2015, 12:46
Location: Sayalonga, Malaga, Spain
My Cars: 1996 XM 2.5TD Exclusive hatch RHD
1992 BX19D Millesime hatch LHD
previously 1989 BX19RD, 1998 ZX 1.9D auto, 2001 Xantia 1.8i auto
and lots of Rovers before that: 1935 Ten, 1947 Sixteen, 1960 P5 3-litre, 1966 P6 2000, 1972 P6 2000TC, and 1975 P6B 3500S
x 1752

Re: Can anyone tell me if this is the speed sensor?

Post by white exec »

What are you checking the speedometer reading against? Satnav/phone or similar?

For a definitive check, your local police may be able to tell you where their "measured mile" is located - usually marks on a stretch of road, or posts at the side. Drive it at steady indicated 60mph, and see if it takes 60s. Good, old-fashioned stuff.

Common for speedos not to start at 0mph, because of errors below 5∼10mph. Should be reasonably accurate (±10%) from 20mph upwards. Worth checking the tyre size - often labelled on an A-pillar.
Chris
Hell Razor5543
Donor 2023
Posts: 13726
Joined: 01 Apr 2012, 09:47
Location: Reading
My Cars: C5 Mk2 VTX+ estate.
x 2993

Re: Can anyone tell me if this is the speed sensor?

Post by Hell Razor5543 »

As I understand it vehicles can have an error of 10% OVER the actual speed of the vehicle, but 0% UNDER the actual speed (although in the UK the speedometer can legally show 10% + 6.25MP/H over the true speed, but not above this). This means that you should never be unknowingly speeding.

https://www.thecarexpert.co.uk/how-accu ... eedometer/
James
ex BX 1.9
ex Xantia 2.0HDi SX
ex Xantia 2.0HDi LX
Ex C5 2.0HDi VTR
Ex C5 2.0HDi VTR

C5 2.2HDi VTX+
Yes, I am paranoid, but am I paranoid ENOUGH?
Out amongst the stars, looking for a world of my own!
User avatar
xantia_v6
Forum Admin Team
Posts: 9052
Joined: 09 Nov 2005, 22:03
Location: France or NewZealand
Lexia Available: Yes
My Cars: -
1997 Citroen Xantia V6 (France)
1999 Citroen XM V6 ES9 (France)
2011 Peugeot 308 CC THP 155 (NZ)
1975 Jaguar XJ-S pre-HE (NZ)
x 825

Re: Can anyone tell me if this is the speed sensor?

Post by xantia_v6 »

It is just the way they build these cars. The German and Japanese manufacturers seem to manage to fit speedometers that are accurate to a km/h or two, but PSA can't.

As a point of reference, our 308 over-reads by 4 km/h at 50, 6 kn/h between 60 and 100 km/h. You just learn the correct indicated points for each speed limit.

You can't fix it by altering the gearing of the speed sensor, as the engine ECU is programmed with the ratio of engine RPM to wheel RPM for each gear and gets upset if the ratio appears to be wrong. Maybe the needle on the speedometer could be moved, but that does not help if there is also a digital speed readout.
Hell Razor5543
Donor 2023
Posts: 13726
Joined: 01 Apr 2012, 09:47
Location: Reading
My Cars: C5 Mk2 VTX+ estate.
x 2993

Re: Can anyone tell me if this is the speed sensor?

Post by Hell Razor5543 »

I have found that the Citroen C5 Mk1 has a VERY accurate speedometer. Compared against a Sat Nav both my previous C5 and my current C5 are almost exactly spot on.
James
ex BX 1.9
ex Xantia 2.0HDi SX
ex Xantia 2.0HDi LX
Ex C5 2.0HDi VTR
Ex C5 2.0HDi VTR

C5 2.2HDi VTX+
Yes, I am paranoid, but am I paranoid ENOUGH?
Out amongst the stars, looking for a world of my own!
User avatar
white exec
Moderating Team
Posts: 7445
Joined: 21 Dec 2015, 12:46
Location: Sayalonga, Malaga, Spain
My Cars: 1996 XM 2.5TD Exclusive hatch RHD
1992 BX19D Millesime hatch LHD
previously 1989 BX19RD, 1998 ZX 1.9D auto, 2001 Xantia 1.8i auto
and lots of Rovers before that: 1935 Ten, 1947 Sixteen, 1960 P5 3-litre, 1966 P6 2000, 1972 P6 2000TC, and 1975 P6B 3500S
x 1752

Re: Can anyone tell me if this is the speed sensor?

Post by white exec »

Physically moving the needle could be an option.
If the instrument is just a voltmeter, driven from the ECU, then a simple adjustment pot on its input might give you (adjustable) correction, to dial back over-reading. Depends on how the instrument is built. Some even have an internal adjustment pot built in.
Chris
User avatar
myglaren
Forum Admin Team
Posts: 25360
Joined: 02 Mar 2008, 13:30
Location: Washington
My Cars: Mazda 6
Ooops.
Previously:
2009 Honda Civic :(
C5, C5, Xantia, BX, GS, Visa.
R4, R11TXE, R14, R30TX
x 4888

Re: Can anyone tell me if this is the speed sensor?

Post by myglaren »

Hell Razor5543 wrote: 08 Feb 2020, 19:23 I have found that the Citroen C5 Mk1 has a VERY accurate speedometer. Compared against a Sat Nav both my previous C5 and my current C5 are almost exactly spot on.
I'll second that James. I was quite surprised at how accurate it is and that is over two cars.
Hell Razor5543
Donor 2023
Posts: 13726
Joined: 01 Apr 2012, 09:47
Location: Reading
My Cars: C5 Mk2 VTX+ estate.
x 2993

Re: Can anyone tell me if this is the speed sensor?

Post by Hell Razor5543 »

As I understand it the C5 Mk1 uses the ABS sensors for the speedometer, and not a gearbox sensor (although I could be wrong).
James
ex BX 1.9
ex Xantia 2.0HDi SX
ex Xantia 2.0HDi LX
Ex C5 2.0HDi VTR
Ex C5 2.0HDi VTR

C5 2.2HDi VTX+
Yes, I am paranoid, but am I paranoid ENOUGH?
Out amongst the stars, looking for a world of my own!
User avatar
white exec
Moderating Team
Posts: 7445
Joined: 21 Dec 2015, 12:46
Location: Sayalonga, Malaga, Spain
My Cars: 1996 XM 2.5TD Exclusive hatch RHD
1992 BX19D Millesime hatch LHD
previously 1989 BX19RD, 1998 ZX 1.9D auto, 2001 Xantia 1.8i auto
and lots of Rovers before that: 1935 Ten, 1947 Sixteen, 1960 P5 3-litre, 1966 P6 2000, 1972 P6 2000TC, and 1975 P6B 3500S
x 1752

Re: Can anyone tell me if this is the speed sensor?

Post by white exec »

If the error is always the same figure, eg +10km/h, across the scale, then reposition the needle.
If the error is a % over-read - eg 22 at 20, 44 at 40, 77 at 70 - then you need to attenuate the voltage driving the meter coil/needle.

If the latter, and you are not able to open up the instrument to examine/adjust, then Speedy Cables, in S.Wales, will correct this for you if you tell them the exact % over-read.

These instruments work by taking a frequency (from gearbox sensor or ABS ring), and converting it linearly to a voltage, which the speedo displays.
Chris
Blazer811
Posts: 44
Joined: 25 Nov 2019, 12:51
Location: Perth Western Australia
My Cars: 2004 Citroen VU Berlingo 1.4i (M59)
x 1

Re: Can anyone tell me if this is the speed sensor?

Post by Blazer811 »

white exec wrote: 08 Feb 2020, 08:58 What are you checking the speedometer reading against? Satnav/phone or similar?

For a definitive check, your local police may be able to tell you where their "measured mile" is located - usually marks on a stretch of road, or posts at the side. Drive it at steady indicated 60mph, and see if it takes 60s. Good, old-fashioned stuff.

Common for speedos not to start at 0mph, because of errors below 5∼10mph. Should be reasonably accurate (±10%) from 20mph upwards. Worth checking the tyre size - often labelled on an A-pillar.
Hi Chris, tyres are the correct sizing for this vehicle, however I do recall the previous owner mentioning that the gear box had been replaced...could this account for the speedo error if it was?
Post Reply