Citroen C3 Owners

Hi, new to the forum so hoping for some help. I know this is a really common topic sadly but hoping for some assistance. My partners C3 Sensodrive has run faultlessly for 2 years but last week refused to start. It has the - on the display where the gear number should be and the radio info screen on dash says eco mode enabled.
I bought a Lexia kit and read the codes for the gearbox. There were no specific ECU faults but it did give 4 which are the following:-
Remote Permanent Fault - Brake Signal switch P1704
Permanent Fault ECU Power Latch P1702
Temporary Fault Clutch Opening Travel P0811
There was also another to do with the gear lever switch which i managed to erase without screenshotting Doh!!

I then erased all the codes in the hope that it might allow me to start but alas no.
I also tried to do an actuator test on the clutch and gear actuators (with a charger and running vehicle connected to the battery) but none of them would run in the test.
I'm scratching my head now. The car is perfect condition otherwise but fearing it's for the scrapper soon. Any advice would be appreciated

Welcome to the forum davedougan

davedougan wrote:Sensodrive has run faultlessly for 2 years but last week refused to start. It has the - on the display where the gear number should be and the radio info screen on dash says eco mode enabled.
I bought a Lexia kit and read the codes for the gearbox. There were no specific ECU faults but it did give 4 which are the following:-

If you clear (by repairing the part or deleting the code - do whatever works permanently) then you can be on the way to fixing the car.

Ignore the eco mode for now.

Try resetting the gear box (it may not help at all, but you have nothing to loose)

Arfur Dent wrote:A couple of things to try then;

To reset the flappy-paddle (sensodrive) gearbox, try this procedure first,

Switch the ignition ON - a dash and "Auto" appear on the instrument panel
Depress the brake pedal and keep pressing
Wait until you see 'N' or a gear displayed (approx 30 seconds)
Release the brake pedal
Starting is now possible again



Try if the first one doesn't cut the mustard;
To reinitialise the flappy-paddle (sensodrive) gearbox ECU, try this procedure

Switch the ignition ON then OFF
Wait 5 minutes
Switch the ignition ON while applying the brake pedal and then release
Wait for 1 minute
Switch ignition OFF and wait for another 1 minute
Attempt to start the car

davedougan wrote:Remote Permanent Fault - Brake Signal switch P1704

You can diagnose this with lexia, but it may just pay to fit another switch.

davedougan wrote:Permanent Fault ECU Power Latch P1702
Temporary Fault Clutch Opening Travel P0811
There was also another to do with the gear lever switch which i managed to erase without screenshotting Doh!!

The lexia can give often you information on how to diagnose and further fault find these errors. Use the lexia to its full advantage to dig deeper.

P0811 sound like a worn clutch

You can attach the screen shots you took from lexia by attaching them using the form below. This can help others see what you see.

Hi thanks for the thoughts on the probems. I've bitten the bullet and sent the ECU off for a test at BB-Reman and hoping it comes back faulty. It's getting a good 12.4v power feed to the simple problem I hoped of no power wasn't to be. The fact that I can't set the ECU to leaning mode or test any of the actuators would suggest to my simple mind that the ECU is the item causing the block.
I'm still learning LEXIA but it was def a good investment as I have a few friends cars which are Pug/Cit that I look after.

davedougan wrote:I'm still learning LEXIA but it was def a good investment as I have a few friends cars which are Pug/Cit that I look after.

If you have the time and patience to learn it money can be saved from going to the dealer



Use the live data part of lexia to see the current status of the brake pedal, keep pressing the pedal and see that lexia reacts with every press. This is to test the brake pedal switch for P1704.

These lexia screen show a similar test on the clutch switch (its a very similar set up for brake and clutch pedal switches).
This can help work out if its the pedal/switch giving a problem or a poor connection or some other fault elsewhere in the system.

Thanks for the info. Really useful to see what Lexia can do. I've sent ECU off to BB-Reman for testing so hopefully the fault is with that which might mean an easy but mildly expensive fix.

davedougan wrote:Thanks for the info. Really useful to see what Lexia can do. I've sent ECU off to BB-Reman for testing so hopefully the fault is with that which might mean an easy but mildly expensive fix.

Good luck! Please keep us in the loop with what BBA-reman say

Latest Update......BB-Reman proved to be a bit of a waste of time. After waiting a few days I called them only to be told that they cant actually test this ECU as they have no equipment to do so. I was told the technician had opened it up and had a look inside and it "seemed ok" so they sent it back to me free of charge.
After putting it back on the car and having another go with Lexia (which I'm getting the hang of) I managed to narrow it down to a result of "Gearbox ECU faulty Replace ECU". So I've tracked on down via BreakerLink for £90 which is worth a try to see if it solves the issue. Will let you know how it goes.

davedougan wrote:Latest Update......BB-Reman proved to be a bit of a waste of time. After waiting a few days I called them only to be told that they cant actually test this ECU as they have no equipment to do so. I was told the technician had opened it up and had a look inside and it "seemed ok" so they sent it back to me free of charge.
After putting it back on the car and having another go with Lexia (which I'm getting the hang of) I managed to narrow it down to a result of "Gearbox ECU faulty Replace ECU". So I've tracked on down via BreakerLink for £90 which is worth a try to see if it solves the issue. Will let you know how it goes.

Thanks!

Sadly after fitting the replacement ECU it still comes back with the "ECU Faulty" error. So now I'm thinking the fault is in the CAN BUS signal setup in that the BSI cant see the ECU so thiks its faulty so now it's going to be a case of checking each of the wires to the ECU from the loom to see if there's a break....Deep Joy!

BSI can see the ECU - BVMP_MA - Sensodrive ECU.



But its been detected as 0.00v input, so I would also check for a power supply to the ECU while you are checking cables.