Technical Battery not charging, no light on dash

[JohnPunto]

Hello Everyone,
I have a 2014 3door Punto 1.2 petrol, and it has been a great car, has taken me to southern Spain and back with no problems, and really never let me down.
Last autumn however the alternator was changed after cutting out in town.
Recently the ABS light came on, and when I read the codes with Multiscan the error pointed to the wheel sensor, which was changed. All good for a week, then ABS light came on and stayed on. Local mechanic chased down a broken wire, repaired it, and happy days, all seems fine.
On a recent run I noticed that battery voltage was dropping, as shown by my cigar lighter connector (gives me extra sockets for satnav etc) which has a volts display built in. Voltage went down to 11.1 when car began to shut down. New battery was fitted which just got me home, with the voltage dropping all the way. There was no warning light on the dash.
After a couple of restarts, voltage went back up to over 13 for a day, but now it has gone back to no charge, with voltage dropping as before.
The garage checked and cleaned earths, wiring etc. and will extract the alternator and get it tested next week. In the meantime I am trickle charging the battery overnight so am able to drive locally.
Multiscan gave the following codes before the ABS wiring was repaired:
Scan vehicle for available modules and check each module for errors...

Engine / ECM
Magneti Marelli IAW 9GF CF6/EOBD Injection (1.2, 1.4)
ISO Code: 7A 07 6D 8C 4F
Errors found:
P0621-15 - Alternator

Body / BCM (Body Computer Module)
Body Computer Delphi (199) MY09
ISO Code: 40 83 51 08 F1
Errors found:
U0019-01 - B-CAN line
B1009-16 - Battery voltage

ABS / ABS/BSM (Brake System Module)
Bosch ABS 8 ESP (2)
ISO Code: EC 07 08 07 57
Errors found:
C0034-01 - Front right wheel speed sensor
C1200-16 - Battery voltage

Electric Steering / EPS (Electric Steering Module)
Delphi Electric Steering (2)
ISO Code: 31 83 16 08 A7

Having read through various explanations of the P0621-15 I shall try running a jump lead from the negative battery terminal to earth to exclude bad earth from the possibilities. Main Fiat is 2 hours away but over the phone said it could be the BCM (mentioning 800 euros).
Is there anything I can do with Multiscan to narrow the possibilities down?
Thanks in advance,
John

 

[GrandePunto PL]

There is no mystery faults whatsoever. The very basics are:
1. Battery.
2. Alternator.
3. Main ground (positive leads failure is less common), corrosion.
4. Starter (the most powerful thing in the car, besides engine).
5. Other wiring, connections.
6. Faulty modules, bulbs, fuses, relays.
7. Current drain. Something is killing the battery over night.
8. Then you have OBD2 (CAN communication) and fault codes, as a last thing to rely on (go for points 1-7 first, always). Of course you check the errors, but you can't trust them right away blindly. You rule out points 1-7 to confirm that error codes are meaningful or they are load of trash.

In reality these are mixed (bad alternator kills the battery and/or starter drains it too much, if it's drained it will try to overload the alternator right after engine starts and so on, cycle continues, add to this water, corrosion - it mess things even more). And various combinations will trip different codes (and in >50% cases they are not pointing to the real problem, sensor code does NOT mean bad sensor).

By the way, example of real Diagnostics (with capital "D"): https://www.youtube.com/c/AutomotiveTestSolutions/videos

 

[JohnPunto]

There is no mystery faults whatsoever. The very basics are:
1. Battery.
2. Alternator.
3. Main ground (positive leads failure is less common), corrosion.
4. Starter (the most powerful thing in the car, besides engine).
5. Other wiring, connections.
6. Faulty modules, bulbs, fuses, relays.
7. Current drain. Something is killing the battery over night.
8. Then you have OBD2 (CAN communication) and fault codes, as a last thing to rely on (go for points 1-7 first, always). Of course you check the errors, but you can't trust them right away blindly. You rule out points 1-7 to confirm that error codes are meaningful or they are load of trash.

In reality these are mixed (bad alternator kills the battery and/or starter drains it too much, if it's drained it will try to overload the alternator right after engine starts and so on, cycle continues, add to this water, corrosion - it mess things even more). And various combinations will trip different codes (and in >50% cases they are not pointing to the real problem, sensor code does NOT mean bad sensor).

By the way, example of real Diagnostics (with capital "D"): https://www.youtube.com/c/AutomotiveTestSolutions/videos

Thanks Grande
Its a new battery
Alternator is a few months old (going to get it tested next week though)
Main ground seems okay (multimeter ohms test), and doubled up earth with a jump lead. Also garage cleaned the earths.
Starter works without any voltage drop
Maybe other wiring?
Main fusebox is dry and seems fine. Will check glovebox fuses tomorrow. How to release the glovebox lid for access?
Battery not losing power overnight.
Multiscan shows the same voltage as the display on the cigar lighter plug
Multiscan graph of voltage shows a sawtooth waveform, not a straight line.
The Diagnostics link you sent, wow! I wish that fella was in Ireland!!
Where can I get a wiring diagram?

 

[AnthonyH]

The alternator is faulty. If it's brand new it's under warranty. If it's actually new to you but secondhand then bad luck, get another one

 

[JohnPunto]

Good stuff AnthonyH, that would be the best outcome, I hope you are right
Thanks

 

[GettinBetter]

Is this an intelligent alternator? i.e. does it have a single wire on the alternator and a sense lead (plug) on the negative battery terminal?

If so, you can check the alternator by unplugging the sense plug from the negative battery terminal, and blip the throttle to the 3/4k range a couple of times, this should cause the alternator to self excite and start charging, controlled only by the alternators internal voltage regulator. Check the voltage at the battery and see if it's charging (~14V) if it is, it may be the Intelligent Battery Sensor (IBS) in the neg battery terminal.

It's an easy check and will cost nothing.

 

[JohnPunto]

@GettinBetter
No, there's just an earth strap on the negative battery terminal, nothing else.
Thanks for the tip though

 

[JohnPunto]

Here is a graph of voltage from switching on to switching off.

 

[AnthonyH]

Here is a graph of voltage from switching on to switching off.
View attachment 439906

I think an alternator works at 14V? So yours is doing nothing?

 

[JohnPunto]

The garage is sending it to be tested tomorrow and i'm hoping it fails the tests! Thanks @AnthonyH