Alternator cable degraded? c4 GP 2016 1.6 HDi

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Elts
Posts: 4
Joined: 19 Oct 2020, 13:03

Alternator cable degraded? c4 GP 2016 1.6 HDi

Post by Elts »

Hello folks,

I've been lurking and searching, but can't find a post directly related to my issues - I'm hoping for some advice.

Our 2016 1.6HDi C4 GP has developed a battery charging warning. Having fully charged the car (off the vehicle) this disappeared, but has now come back.

With the engine running the voltage across the battery (and from the alternator output to earth) was around 12.6v. I don't yet have an o'scope handy to measure the PWM signal to see if the alternator was being asked to supply - with the battery being freshly charged I suspect it wouldn't have been tasked to charge anyway at that point.
I also measured the resistance / continuity between the alternator and batter terminal (both ends disconnected) but got somewhere in the realm of 70Kohms... which I wasn't expecting as I assume that the feed from the alternator is direct to the battery, and not via any other circuitry. Is there another parallel circuit at play here?

The routing of the cable from alternator to battery terminal appears to vanish off behind the engine, so I can't physically inspect. Does anyone have any advice or other areas that I should be considering?

Could this be as simple as the cable having degraded, and requires replacement? If so, how is it done, given that it appears hidden behind the engine?

Thanks in advance for any info, help or encouragement!

Cheers,

Elts

petarc1971
Posts: 14
Joined: 01 Mar 2019, 20:50
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Re: Alternator cable degraded? c4 GP 2016 1.6 HDi

Post by petarc1971 »

The alternator should charge 13.4v, which means yours doesn't charge. In the case of Citroen, the charging warning is activated late. In your case, the problem is in the alternator itself (charging regulator, stator, rotor, diode plate) or the pulley with the clutch is slipping.

Elts
Posts: 4
Joined: 19 Oct 2020, 13:03

Re: Alternator cable degraded? c4 GP 2016 1.6 HDi

Post by Elts »

Thanks @petarc1971 - any idea why I am experiencing such a high resistance on the charging cable? I am loathe to replace the alternator if a simple cable replacement will rectify the issue.

petarc1971
Posts: 14
Joined: 01 Mar 2019, 20:50
x 2

Re: Alternator cable degraded? c4 GP 2016 1.6 HDi

Post by petarc1971 »

I have no idea about the resistance, you should look at the wiring diagram and check if the cable goes directly to the battery. There is an alternative way to check the alternator if you are skilled.

Elts
Posts: 4
Joined: 19 Oct 2020, 13:03

Re: Alternator cable degraded? c4 GP 2016 1.6 HDi

Post by Elts »

Does anyone have a wiring diagram for this particular circuit?

petarc1971
Posts: 14
Joined: 01 Mar 2019, 20:50
x 2

Re: Alternator cable degraded? c4 GP 2016 1.6 HDi

Post by petarc1971 »

I watched a video clip showing a similar problem as yours, it is a c4 picaso model that has large headlights, the owner had a problem with the alternator where he drew an improvised diagram in the clip in which the wire from the alternator has a connection to one of the computers, so it is possible that great resistance arises because of it. Of course you need to check that.

RichardW
Forum Treasurer
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Re: Alternator cable degraded? c4 GP 2016 1.6 HDi

Post by RichardW »

Does it have stop/start functionality?

Elts
Posts: 4
Joined: 19 Oct 2020, 13:03

Re: Alternator cable degraded? c4 GP 2016 1.6 HDi

Post by Elts »

RichardW wrote:
20 Oct 2020, 19:25
Does it have stop/start functionality?
Hi Richard, yes it’s got start stop.