C3 Snowflake Sensodrive

[Jasper99]

My wife tends to get this problem... I haven't had it yet, although I only drive her car occasionally.

Three beeps and the dreaded snowflake... dashboard shows a hyphen no gears visible and can't get them selected.

Ok so reset the gearbox, foot on peddle for 30 seconds and car works for a few weeks, then same problem occurs. This time car won't restart and after connecting / disconnecting the battery to no avail, finally decide to recharge the battery overnight and hey presto gears are reset car is good to go.

Wife is now unwilling to drive the car. I ask the local citroen dealer to do a diagnostic and enquire whether I can get a software upgrade for the gearbox ecu.... they aren't taking any bookings until the 22nd...20 days away, it will cost me £78 + vat for the diagnostic and if an upgrade is required they will provide it.

Local garage a couple of miles away offers to do the diagnostic £45 and give me the following readout,

- faults p1704 can message brake signal, signal faulty
p0750 signal from automatic transmission gear not switchable
p1702 transmission control unit signal during run on impausible
p1755 clutch actuator position sensor, position faulty
p0560 voltage supply control units singal not in range
information found e.c.u upgrade can cause this fault

Can anyone translate and explain what the above may mean and a way forward.

From previous posts I am wary of suggestions of gearbox actuator or clutch actuator replacement as more often than not this doesn't solve the problem, plus of course appears to cost a lot of money

[wheeler]

My wife tends to get this problem... I haven't had it yet, although I only drive her car occasionally.

Is this a clue ? does she drive it with both feet like a go kart ? People that drive autos like this can sometimes slightly overlap when pressing the accelerator the ECU's don't like this & think its a problem & can sometimes throw up a brake signal fault. Just a thought.
How long have you had the car & is this a new problem ?

[Jasper99]

Had the car 8 years but this has started happening last 3-4 months