Berlingo 1.9d Speedo Faults

[carpymick]

Hello all,
now I know there are a lot of posts across different forums about speedo issues on these Berlingos but Ive never found a definitive answer or solution.

Here goes someone may be be able to assist in my problem speedo.

Firstly I have a Berlingo 1.9d 2005 which is a great little van for my fishing runabout . I fitted a new Bosch speedo sensor as the speedo kept dropping out. This usually cures the icky speedo but not this time. The speedo works at times but not others.

Here is my list of symptoms to date.

On starting the engine the speedo will often but not always flicker about giving a varied reading of 10 or 20 mph although vehicle is stationary.
When pulling away speedo will settle down for a random distance and then drop suddenly to zero. When this happens the mileometer also stops working.

Now the odd bit, if I pull over and switch everything off and wait about 1 minute listening carefully I hear a relay in or close to the BSI click, at this point I can start engine and all will be well for the duration of the journey. I noted that in that minute of waiting the wipers can be operated even though ignition is off. The next startup such as a drive home after that journey may or may not result in speedo stopping. A fresh start the following morning always results in the same symptoms. Nearly forgot, When parking van after a no speedo trip the dash stop light comes on and a beep operates for a few seconds.

I intend to get this sorted once 15th March is here (fishing close season) as I can then spend some time investigating. I do know speedo drive is sound as I had to fix a leak from housing plate while replacing clutch and Ive checked sensor is connected firmly and cleaned contacts with contact cleaner. 

Ive not checked anything else as yet but I am intrigued as to how speedo is receiving a signal when vehicle is not even moving. Ive not scanned for any faults as yet but will in due course. I intend to swap another sensor from another van at work that is functioning correctly just in case I have a faulty new sensor. 

Any suggestions most welcome. Last resort a GPS Speedo from ebay

[Gryffindor]

I have a similar problem to your dropping out with my 53 1.4 petrol M59; it was assessed by a trusted Citroen specialist last week and they will be attempting a repair next week (while they're also doing the head gasket btw).

My car had sat for a couple of months early last year, then when I first used it again, the speedo and mileometer were not working. They have never worked since, not even intermittently. At the same time, I also get three even bleeps whenever I turn the ign on or off, which seems related to me but I'm not sure.

One thing I have picked up along the way is that when both the speedo and mileometer fail but nothing else does, then the fault is most likely with the speed sensor or its circuit. This may be wrong of course though!

After reading up advice given on here, I asked the garage to check the speed sensor. It could be loose, playing up, or dead. They immediately agreed that this was the most likely cause and checked the sensor and cleaned it. It appears to be dead so they have ordered a new one to be fitted next week (btw, they said it cost them about £30 from Euro Car Parts against £70 from Citroen).

But they warned me that this might not fix the problem, because the fault could lie anywhere from the sensor to the instrument cluster, although I suspect they are more familiar with pre-canbus cars than post and I wonder about a canbus operated cluster being at fault here. But in any case, the fault could lie with the cable from the sensor to wherever it goes to, or with wherever it goes to (ECU/BSI?) or with the connection from that to the cluster, or with the cluster itself. We will see what happens when they try the repair.

I don't have your spurious readings at idle, though I suppose it is possible that I do but it is masked because the speedo always does not work. To my mind, such an intermittent fault must be related to an incorrect electrical signal.

I think the speed sensor works by detecting the passage of a rotating magnet on the driveshaft; this would produce some sort of waveform whose frequency would relate to the driveshaft's speed.

If so, then it would seem that some sort of spurious waveform type signal is being picked up when you are stationary, perhaps some sort of interference from another system, or a fault with whatever detects the waveform and turns it into a digital signal for the cluster.

Or alternately it could be a contamination of the digital signal, perhaps from some other faulty component or signal on the canbus.

Only guesses on my part but I hope it helps.

Because your speedo is only intermittently dead, then there may be a separate problem along the lines of a loose electrical connection, an electronic component overheating and failing then recovering once it cool off again, or it could be that a digital signal is getting lost, perhaps as a fault of whatever generates it or whatever receives it, or as a result of a wrong instruction being sent to them.

Lastly, I think that relay click a couple of mins after killing the car is normal - note that the general advice given on doing any work to the ECU includes waiting some minutes beforehand, presumably for this relay to do its thing. Others will know for certain, but my guess is that when you firs take the key out, many systems in the car (especially the ECU/BSI?) remain either active or in a standby mode and can be reawakened by some sort of activity. But then after a delay, everything is finally put to sleep.

You say that the speedo works fine if you wait for that relay click before starting the car again. Are you saying that it is still faulty if you start the car without waiting for the click? If so, again I am only guessing but because turning everything off clears the problem, then perhaps it exists within the car's ECU/BSI as some sort of programming or software problem or a wrong setting?

Over to others with knowledge and experience as well as guesses...

[carpymick]

Thanks very much for your input. It is much appreciated.

You are correct in your assumption that if I start the engine before relay clicks in/out then the speedo will not be working. Waiting till after click it will work just fine.

I have heard of cases where a faulty diode in the alternator can produce an ac current wave form throughout the system and thus set up an induction into another sensor. If that was the case I feel it would be there all the time. Always worth eliminating a few things though.

Did you ever get yours sorted?

[Gryffindor]

You peaking of induction in motors, combined with your odd readings in the first few moments, did make me wonder about the starter motor - but surely it would stop spinning very quickly?

As I said, mine is booked in for next week; I won't know the outcome until at least Thu/ But fingers crossed it can be sorted without pulling the entire wiring loom out! I'm already considering using something like Torque Pro if it can't be fixed, though I suspect that would only give me a speedo, not the mileometer function?

[Gryffindor]

Your mention of induction from motors reminds me that I did wonder about the starter motor - but surely it should stop spinning very quickly.

Mine is booked in for next week and I won't know the outcome until at least Thu, maybe later. Fingers crossed the new sensor fixes things and the whole wiring loom doesn't have to be pulled out! I am considering using something like Torque Pro if my speedo can't be fixed, but I suspect that won't give me mileometer function as well.

Update: since a new sender will be fitted anyway, if the problems are elsewhere, then maybe I can take my own readings directly from it and devise some sort of bespoke readout device.

[carpymick]

I will be sure to post fix if I manage to get to the bottom of it. No time till mid March to start investigating.

[Gryffindor]

FWIW, my car sailed through its MOT last Nov with the speedo and mileometer dead.

[carpymick]

I will be sure to post fix if I manage to get to the bottom of it. No time till mid March to start investigating.

Well, I finally got around to taking a look at my speedo issue and am pleased to say its fixed.

I disconnected wiring at speedo sensor and checked supply which was good only showing a minuscule voltage drop compared to battery voltage.
Next I tested for voltage drop on earth side this showed a small voltage drop that I felt was within limits. I then checked earth connection with sensor unplugged and ignition off using ohms function to check for resistance. This showed a very small .010 resistance.

I then traced the earth wire back through the loom, snipping off tape and removing conduit to be sure I followed correct wire. It went across the bell housing and around the front of the engine block and just above the oil filter there it was . A 10mm bolt with an earth wire that was as loose as heck being finger tight and about 2mm out of its fitting. I removed bolt completely and cleaned up all mating faces and refitted screw and tightened.

Quick road test and all is good. Its never been such a nice smooth speedo function.  Silly thing is Ive had the van 3 years and speedo has got steadily worse with me fretting the BSI will be knackered and its turned out to be really simple fix. 2 hours testing and tracing and 10 minutes to fix.

Worth remembering loose or bad earths do some funny things, strange how only speedo seemed to be affected by this earth though.

[Gryffindor]

Well that is amazing - well done!

[Kieron G]

Thanks for posting this. Might save me and other members a lot of time and stress some time in the future