in eco mode and not start. Now all fixed!

Hey people, first post, but somewhat similar issue to many other users

I've got a 52 plate C3 1.4 SX with approx 101k on the clock. Owned it since 85k. A few weeks ago it overheated and the expansion tank released the water due to the pressure. Turns out the fan wasn't coming on .. got towed home and since then the car has been sat outside the house. I made a point of starting it every day (missing the odd day here and there) just to make sure it kept on ticking.

One day i went to start it, and it wouldn't - it would tick over but not fire into life. Stopped trying to start it, let it sit, then tried again but same thing. Since then it hasn't started, just turns over. I've since replaced the fan, but I can't test it due to not starting

The car is currently stuck in eco mode, and the ECU won't respond when trying to interrogate it. I've tried my own OBD reader, and the RAC man has tried his, but it won't respond. I've tried resetting the ECU using the 'power latch' method, and by another method. All the fuses are good, I haven't removed the fuse box to check if that's got wet yet, but doing that tomorrow, as I understand this can be a problem (and it's certainly something I've seen reported before).

The fuel pump however doesn't prime when you turn the ignition on, which made me wonder if the pump was gone, but the flotation thing is registering the level of fuel on the dash correctly (not sure if this means anything regarding the fuel pump working properly)

As it stands, I need to charge the battery as it's a bit low now. Is it possible to test the fuel pump by applying voltage to it? Or is it unlikely the pump is dead? What is most worrying is that the ECU isn't responding when you try to read it, which sounds like it'll cost £££ if it's dead

Welcome to the forum crowarth

As it stands, I need to charge the battery as it's a bit low now.

How is the car with a charged battery?

Just starting the engine every day will drain the battery quickly as its not getting recharged between starts.

With a charged battery it's still the same - not starting, all the previously mentioned issues. The only difference is the battery is charged and you can tell, because the starter motor is quote obviously doing its job well, apart from starting of course

Welcome to the forum crowarth

Thanks

crowarth wrote:With a charged battery it's still the same - not starting, all the previously mentioned issues. The only difference is the battery is charged and you can tell, because the starter motor is quote obviously doing its job well, apart from starting of course

Do you get anywhere with OBD?

If not, its worth checking fuses, engine bay and glovebox.

https://citroenc3owners.com/citroen-c3-t ... -t129.html

https://citroenc3owners.com/citroen-c3-t ... -t157.html

OBD fuse is in the glovebox, but check them all.

OBD doesn't do anything - it cycles through all the protocols but the car doesn't respond. Admittedly, I haven't checked those fuses yet, that's a job for tomorrow when there's a bit more light than now, so I can get at them.

The RAC guy who came out couldn't really get to them in the dark so they're the one thing that hasn't been checked. I did notice a bunch of pretty large fuses on the underside of the engine bay fusebox, but a quick glance at these suggested they were all in working order. Thanks for the links, starting to build up a nice collection of documentation!


On the plus side, I found an unused grommet that I can route a power cable through!

crowarth wrote: On the plus side, I found an unused grommet that I can route a power cable through!

If you get a chance can you add the grommet location to https://citroenc3owners.com/citroen-c3-a ... -t609.html, if you can get a photo, that would be great. Maybe a job for the summer?
Thanks.

Do you get anywhere with OBD?

If not, its worth checking fuses, engine bay and glovebox.

https://citroenc3owners.com/citroen-c3-t ... -t129.html

https://citroenc3owners.com/citroen-c3-t ... -t157.html

OBD fuse is in the glovebox, but check them all.

So I've checked the fusebox in the glove-box, and they look good. Battery has been charged and is definitely more healthy now. However, the problem persists. Stuck in eco-mode, the usual circuits are disabled as a result, and the fuel pump doesn't appear to prime the engine (you can't hear the pump at all). Naturally, the car doesn't start as a result. I've noticed that the gearbox is slightly stiffer (it's been sat for a while!).

Tried the OBD again, the ECU doesn't respond ... what tells the car it's in eco-mode? Does the ECU display that message on the dash? If it does, does that suggest the ECU is alive to some extent? Not sure what else I could check:

Fuses in engine bay look good
Fuses in glove-box look good
Battery is fully charged
Fuse box in engine bay is dry on top and underneath
ECU plugs are fully pushed home

Car is in eco-mode, circuits disabled as you'd expect
Fuel pump doesn't kick in when you turn the ignition on
ECO does not respond to OBD (this is the bit that worries me)



Edit: Just tried resyncing both keys, and have removed the after market head unit. Worth noting all elements of the car functioned properly after the head unit was installed, for a significant period of time.

So after sitting on the road outside my place for 3 months, she lives again

Turns out it was a single wire from the ECU that had rubbed and exposed the core, and eroded, causing the ECU to not respond and the car to be in eco mode and not start. Now all fixed!

When i get home, i'll post a picture of the grommet location

Hi crowarth, thank for the update. Glad things are working again.