Taxi Driver Online

Hi,
Wonder if anyone out there can help to identify a problem and the solution.
The company I drive for, has a fleet of 30 E-Class Mercedes from 2007 - 2011. We use Digitax meters, i'm not fully up to speed with the technical side of things but they work on distance, (when the 'hired' light above the fare is not flashing) & time when it is flashing & the vehicle is stationary. Recently we have had a problem with the meter in a 60 plate estate, its an intermittent fault where the hired light starts flashing when the vehicle is moving, effectively meaning that the meter is in 'time mode'. This can occur at any time during the journey & once the fault starts it is permanent & continues for every journey afterwards. The only way to rectify the fault is to wait until the meter goes into 'sleep mode' when the ignition is switched off for a period of time, approx 20 minutes, or unplug the electrical connections from the meter & plug them back in. This cures the fault but only until it occurs again, which can be the next day, next week or two weeks later. Our fitter has replaced the meter, along with the wiring & the canbus has been replaced twice but still it persists & he is now at a loss as to what is causing the problem. I drive this particular car & i'm obviously keen to see this fault rectified. If anyone can help with any pointers, I would be very much obliged. Many thanks, Simon.

The meter isn't getting pulses to tell it the vehicle is moving (or how fast). Most likely a bad connection in the pulse wire.

_________________

http://wingsoverscotland.com/ http://www.newsnetscotland.com/

or a cambus wire broken green/white twisted wire
its it a auto then check the wire beside the gear stick (left hand side as you look down)
if you have diagnostic then check the dash board if fault shows then thats your problem
may also be a problem with the fuse box under the bonnet (this is a major problem with mercs, easy to change as all the wires just plug in under it (called sam unit... this is where i place my money)

we run a fleet of mercs and i have to fix them

i hope he has not taken the the pulse from the ecu socket, also has he taken the earth wire from a earth point from the body and not tapped into what he thinks is a earth( again cam wire)
never tap into other earth or 12v wires from other equipment
daz

I had exactly the same problem, only fixed by unplugging the wires from the meter and waiting a few minutes, but this only worked if the PDA/meter/radio/ignition was completely shut off. Used to happen once a week and then transferred the kit to a new vehicle (new wires and sensors) where it was fine for a few months then over about a month did it twice more - fine ever since !

Never got to the bottom of it but guessed one of the pins on the meter (also a digitax) had a bad connection. Strange that it could only be resolved if the meter was off, you'd think if it was a bad connector it wouldn't matter.

It can also depend on the type of CAN bus unit being used. Some need a permanent 12V feed (they the automatically shut down a while after switching off the engine), others need the 12V feed from the ignition switch.

Like Daz says, earthing should be direct to the chassis/body, there are plenty of places for that.

One other possibility is that the meter's pulse wire has been pinched at some point and so has broken strands, which can cause a loss of signal intermittently.

We get the same fault. Turn the meter off then turn the ignition off and remove the key. Wait a few minutes then turn the ignition on and start the meter.

Many thanks to Gusmac, Daz800, Sasha & Zia for your help, i'll pass on your posts to our fitter. Also thanks to Nidge2, no doubt it will occur again & i'll be keen to try out your tip when it does. I will let you know what happens.
If anyone else can help, please do.

Thanks again, really appreciate all your replies

also worth asking and checkingif the canbus unit fitted is the latest or correct version software for the merc as it is common for some fitters to re use the clients old unit from an old car or maybe a left behind unit from another job / customer considered a bonus .Which to be fair may be ok but a good installer should at least cross check the software version on the unit will work without issue on a much newer vehicle.
We have recently had that type of issue with older canbus units being refitted on new model skoda octavias ,which gives exactly this problem randomly .
If we then fit a latest software cannect / M8 unit the problem goes away never to reappear.
hope that HELPS

also worth asking and checkingif the canbus unit fitted is the latest or correct version software for the merc as it is common for some fitters to re use the clients old unit from an old car or maybe a left behind unit from another job / customer considered a bonus .Which to be fair may be ok but a good installer should at least cross check the software version on the unit will work without issue on a much newer vehicle.
We have recently had that type of issue with older canbus units being refitted on new model skoda octavias ,which gives exactly this problem randomly .
If we then fit a latest software cannect / M8 unit the problem goes away never to reappear.
hope that HELPS