Problem starting Citroen C4 2016 blue hdi

[stephenfreeman]

Good Morning,

We appear to have an electrical problem. There appear to be a variety of possible causes.

Symptoms:
For some time now, when attempting to restart the car after a period switched off but with the key fob still in the slot, we can get reprted faults such as such and such door is open or even window. Of course they haven't been, but easily remedied by opening and shutting said door etc.

More recently a problem seems to be increasingly common is the inability for the car to start. When it is cold, it usually starts first time, but with the warmer weather it is becoming increasingly problematic. Put the keyfob, press the clutch pedal down and press the stop/start button, it just switches off.
Eventually after much clutch pedal pressing (well sometimes not much) and button pressing it does start.

I think I have 4 possible culprits:
1. Slave cylinder on the clutch. know there has been a problem for some time but more of a niggle than anything else
2. BPGA faulty
3. Battery needs replacement. We don't use the stop/start facility but it is a nine year old car which we have had since before COVID, so logic tells me to be suspicious even though when it starts it starts easily.
4. Key fob or slot

Think it has to be one of these. From the symptoms which do you consider the most likely?

[stephenfreeman]

Just tried it again this morning and of course it started first time, tried again no problem. I had given all the relays in the box near the battery a quick push just to make sure ((didn't remove any).

still mystified

[stephenfreeman]

Of course it hasn't been a problem since! Either the change in the weather or more likely me pressing down firmly on all the relays in the box near the battery has resolved it for the time being at least.

[stephenfreeman]

Well, return of the heatwave and it won't start! Engine cold so not that, I am baffled!

[Sanvish]

Probably battery check would be my first thought. From what I understand the battery is 9 years old. A simple voltage check to earth (do not check posi to negi on the battery if you're not aware) should suffice.

If you have a jump starter, try that and if it starts, then it points to a weak battery.

[stephenfreeman]

I have already checked the voltage, it reads 12.5vdc, which I understand is OK. I know it is a stop/start enabled car but we have never used it since we bought it in 2018 (past experience with other car tells it is not to be relied.

Having read a bit more I think it is probably the BPGA unit, given that we have had some spurious warning messagesfor some time before, usually about a door or the boot being open when it is not and windows not opening/closing as I think they should.

I think that I probably have to do a BSI reset but having read the info about this, I am a little confused about the sidelights having to be switched on. As far as I know they can only be on if the ignition is switched in, I know that later/other models have two options for the sidelights, auto and manual ours doesn't. So if the sidelights are off is this going to be a problem?

[mickthemaverick]

Check this video of the BSI reset and maybe it will help your thinking. When it requests sidelights on that is referring to putting the switch in the on position.:

viewtopic.php?p=843863#p843863

[stephenfreeman]

I'll give it a try tomorrow but the car in the video is quite a lot different. Ours has a starter button, you are supposed to place the key fob in the slot, depress the clutch and press the button.
Normally fires straight away but when weather very warm , nothing happens. I do notice that even the fan etc doesn't come on either. No auto position for the sidelights either.

So not sure what will happen.

[Sanvish]

I have already checked the voltage, it reads 12.5vdc, which I understand is OK. I know it is a stop/start enabled car but we have never used it since we bought it in 2018 (past experience with other car tells it is not to be relied.

Having read a bit more I think it is probably the BPGA unit, given that we have had some spurious warning messagesfor some time before, usually about a door or the boot being open when it is not and windows not opening/closing as I think they should.

I think that I probably have to do a BSI reset but having read the info about this, I am a little confused about the sidelights having to be switched on. As far as I know they can only be on if the ignition is switched in, I know that later/other models have two options for the sidelights, auto and manual ours doesn't. So if the sidelights are off is this going to be a problem?

12.5 V is marginal. A good battery at rest should be 12.6V +. You can do another test with the battery. Whilst you are holding the probes ask someone else to start the car. If it dips below 10v during the starter pull then there is an issue with the battery

Batteries don't need to be used to degrade. They age and lose their capacity to retain charge and supply load over time too.

[PaulC5]

If pressing the clutch pedal helps then it may be a problem with a switch on the pedal. If you are thinking of spending money on lots of parts hoping to fix it, then you might be better off visiting a dealer to check the fault since this might save a lot of money on unnecessary parts.

[stephenfreeman]

1) Depressing the clutch pedal is part of the starting procedure, if you don't do it then the car will not start. I should clarify that following the starting procedure of putting the key fob in the slot, depressing the clutch and pressing the button does not energise the starter motor at all, the display comes on etc though. So yes it could be a faulty switch etc but having read a bit more I find that warm weather etc can cause the battery to lose power (i.e. amps not necessarily volts). So I am going to check the battery out a bit more, it is about 9 years old after all, so probably needs changing anyway.
So still thinking it is either the BPGA or the battery or both . Given the cost, I'd like to check which one it is. Of course it could be the switch on the clutch pedal, wherever it is or some dodgy connection somewhere.

I hope too know more later today.

[RichardW]

If the clutch sensor is at fault, then you should get a message that you need to press the clutch to get it to start. Generally batteries work better when warm. I'm sure I saw similar on FB group last week, where the car would switch on, but then off rather than cranking. I would be leaning towards the BPGA, but really needs looking at with some decent diagnostics with live data to see if there is a hint.

[stephenfreeman]

Have just done a BSI reset. I have just hooked up a relatively OBD unit. No codes stored. Battery reads 12.2v, so think it probably is that, cheaper than a BPGA. Starter doesn't try Fingers crossed

[stephenfreeman]

Not the battery. It is definitely to do with the pressing the clutch action. Just don't know where the switch/sensor is at the moment. If I give the clutch pedal a good hard shove it works. So bad connection etc

[PaulC5]

This might help but is from 2011 http://c4owners.org/plugins/faq/faq.php?0.cat.2.224