A mystery force - car will start but won't move

[mikeyr]

Hi all,

First post here, actually own a Citroen C Zero but believe it's the same internals. Only owned the car a few weeks but already had a couple of issues. It has done 91000 miles over its ten year life span but you'd not know it to look at it.

A few days after purchase it did a few short trips and then wouldn't go into ready mode. Air con was weirdly grumbly before that also but new battery seems to have resolved that issue. Easy enough fix, needed a new 054 battery and all has been fine since.

Fast forward to today and we had very heavy rain/wind last night. This may be related but keeping an open mind. Car was on charge last night outside and has a full charge. Car went to ready mode but when I drove off it felt like the rear tyres were sticking, almost as if the brakes were still applied. It went about 200 metres before juddering to a halt and the yellow battery/exclamation light came on. Car refuses to move. Take key out and restart and car starts fine UNTIL i try to move. Same symptoms whether in D or R. or even B. It almost immediately either judders to a halt or refuses to move, every time bringing up the same error light.

My first thoughts were that the brakes had seized in the rain. I've jacked up the back of the car and both driven wheels spin freely so think I can rule out the drum brakes? Haven't checked the fronts but did manage to easily push the car back to the house so can see no evidence of the fronts being an issue either, especially as would expect back wheels to spin under power even if fronts were stuck on.

I don't have a code reader (other than an ELM327 which don't think works with these anyway) and my next plan was to pop the back end up on bricks to see if rear wheels spin on using accelerator when not fighting friction of road. Figure that would give some indication whether it's a manual or electrical issue. And some time in the sun today in case there is water ingress somewhere?


Can see no evidence of a leak from the gearbox at rear so doubt it has lost all the fluid from there overnight. I'd expect (but could be wrong!) that if was short on lubricant would be making painful noises but still progressing?

Short version :
Can starts great, 12v healthy. Won't move more than half metre or so as if some invisible force is preventing tyres from spinning. Car knows things are wrong because is shutting down with yellow warning light. Doesn't seem to be brake issue.

Any suggestions? Next step will be to take it to someone to look at but being unusual car if anyone has recommendations for EV specialists in Hampshire, UK, please do let me know!

We are now an all EV family having an ID3 for day to day stuff and this little car for times we need a second car. It's been going at least a few miles every day so Isn't through lack of use!

Thanks all

 

[mikeyr]

Should add, the gear selector moves freely and looks (visually at least) that the linkage underneath car is moving about okay. No issues with is moving between modes on screen. Just tried again and car moved slightly but again seems to be fighting against something before cuts out. Really does feel like brakes are stuck on but again, can push car fine and handbrake lever seems to engage/disengage easily.

 

[mikeyr]

Small update (and I'll keep this thread updated with progress in case useful to others). Lifted front and then rear wheels afterwards (safe and securely!) and checked all wheels would rotate. They do although fronts definitely got more drag than rears. With rear wheels in air I put car in reverse, the wheels turned slowly then would stop. They'd go a little faster if I put accelerator further down. Always coming to a stop of own accord which assume was likely software related but always without the yellow warning light. Same in drive. Incidentally, press the brake pedal when stationary more than five times and the car beeps angrily at you

I cleaned the linkage a bit with a brush and sprayed on some GT85 to see if was any way/dirt trapped and on next attempt the car moved. in fact, it was fine and smooth for about a mile, tried some heavier braking and then putting foot on accelerator on a longer 60mph stretch of road and after couple of goes it shut down again, leaving me to coast to a halt, thankfully near a layby.

Took a few restarts and some juddering to get me another half mile when it got worse again. Tried moving the shift lever a little from left to right in case was a loose connector but didn't seem to help.

Is now back at home and the problem isn't solved although we've maybe made some progress. Can't see that this is a binding brake issue, no ABS lights etc. Interesting that the linkage seemed to make a difference but then again I've not had any issues with the dashboard showing wrong gear or the like. Think would flash but could it be a sensor that is intermittently recording the wrong gear?

Could a faulty ABS or other type of brake sensor be messing with the system? Could the linkage or sensors need replacing? Could I have a huge bill to pay coming up? So many questions!

 

[kiev]

My first thought is on the sensor for gear position on the gearbox. It is really a dual sensor with two sets of contacts for each position, and they must match. So dirty electrical contacts might cause a mismatch or open circuit, etc. Just my guess and that you sprayed in that area and noticed a slight difference.

Your troubleshooting would be much easier and quicker if you could scan and read out the DTCs associated with the faults. The ELM device might work to read the codes. i have both hard-wired and radio (BlueTeeth) type of spam tools that can read codes, most all of them should be able to read codes (that is their purpose). May not clear codes, but just getting a clue of where to look will be the biggest help.

Fold down the seats and Open up the engine compartment under the rear storage area carpet and have a look around for open covers, leaks, rodent nest or wiring harness damage, etc

 

[mikeyr]

Thanks Kiev, interestingly the Citroen and Miev have a slightly different gear indicator design on the dash, I've had no issues with it flashing or not showing the gear I'm actually in but like you said, if the two don't match could be an issue. Are they fairly easy to swap over? Does the linkage need adjusting too normally?

Hoping I can take it to a local mechanic and show them this thread...
https://www.speakev.com/threads/c-zero-ion-charging-failure-due-to-stiff-gear-lever-mechanism.98153/

 

[mikeyr]

(at least i've seen some videos where P D N B C etc are all smaller font and visible but others that, like my Citroen, only display the one large current drive mode, e.g. D)

 

[kiev]

i've never tried wheels-in-the-air driving mode, but it may be that the traction control detects rear wheel turning, but front not, and pulls back the torque?

check the connector and wiring to the accelerator pedal, for dirty contacts or chewed or cracked wires, etc

 

[mikeyr]

Did wonder that!

For those that have had the sensor issues, did these show up as fault codes?

 

[mikeyr]

Just had a thought, if was the sensor wouldn't it trigger after three seconds if thought the gear readings were conflicting? So could test that with a stationary car???

 

[mikeyr]

Well, tried that and no issues. It's still 50/50 on jerkiness when moving forwards or backwards. Recommendations on cheapest way to read a fault code folks?

 

[michael8554]

After very heavy rain on Wednesday 20th September, our MIEV brakes started grabbing.

Okay at 30mph, but by the time the speed was reduced to walking pace by the brakes, the brakes came on full.

This was repeatable.

Next morning, on application of the brakes, I could hear the brake pads clearing rust or crud off the disks, and braking was fine.

 

[mikeyr]

It has been driven since for a couple of miles, wheels seem to be free. Only other thing, and I'm grasping at draws now before deciding whether to get it to a garage or shell out for an OBDlink MX, would be a throttle position sensor. Can't find any evidence that these go wrong on the triplets though?

 

[kiev]

Most intermittent faults are due to wiring or connector issues, especially in high humidity or wet conditions, rodent damage, etc. First thing to do is check all wiring and connectors, cheapest option (free to do) Keep your 12V battery full charged while it sits waiting.

 

[MickeyS70]

Recommendations on cheapest way to read a fault code folks?

Sorry to hear about your troubles
HobDrive claims to work with the most basic OBD dongles, try it with your ELM327, setup is a bit tricky and most likely you will need the paid version. The app can read and clear DTCs, I tried it myself but with a more expensive OBD Link LX.
Mickey

 

[mikeyr]

There is a lot of Mikes, Mickeys and Michaels on here :lol:

So update, I THINK I had a couple of issues. One was brakes binding, enough to make car think there was something wrong with the power output. I have no grumbling today from the rear end (make own joke here). I've done a couple of 50mph heavy braking sessions in neutral to clear any rust or residue off of the brakes. I'm going to try leaving the handbrake off whilst it is on our very flat driveway and just have it in park.

Cleaning the shifter seemed to help too, going to give it a proper brush off over weekend. And my C Zero has had the shifter modification to allow the gate to select B and C modes. But it was poorly cut out for these two gears so have quickly filed back a bit more room for stick to nestle in when in B mode. And C mode never really appeared as the shifter hadn't been cut back far enough. Another 4mm sorted that and might help the car if was getting confusing signals about being in B or C mode from shifter moving around on edge of both positions.

Guess we'll see if returns when rains again. At which point might be looking at sensors getting wet. Will update if have more issues.

 

[mikeyr]

Should add I REALLY like this car when it is doing what it should. The next few days will be pivotal on its chances of remaining part of the family...

 

[kiev]

O-o-o-h...the cutouts for the gear shifter...likely an important clue in this mystery...

Some cars have two sensors with linkage,

 

[mikeyr]

Trying to work it why Citroen/Peugeot didn't include B and C modes to start with. But perhaps it was a worry that B mode might not use the brakes enough thus leading to issues like binding? That's purely speculative of course!

 

[PV1]

Curious on the current state of this. Having worked on a ton of eBikes with 3-phase motors, I’m inclined to lean towards something with the drive motor. Perhaps check the sensor wires and connections between the drive unit and MCU. This harness should be on the end of the motor closest to the right wheel.

With eBike motors, if the controller doesn’t receive a proper signal from the encoder/hall sensor, it’ll often go into a rudimentary drive mode that makes quite a racket and is rough, very easy to mistake for a physical problem. It technically is a physical problem with the sensor or wire, but the noise and vibration is entirely caused by electricity.