2015 Grand Picasso II B78 2.0BluehDI 150 EAT6 battery life

[WillyR]

Greetings all

Having just returned from a 1400 mile trip to the South of France, I am in a bit of a quandary.

I have had an intermittent Battery Protection unit (situated on the front of the battery) fault for a couple of years, but during this trip it threw ALL its toys out of its pram. Luckily, I didn't have to take the car to a garage. Every day, on starting, the engine did not complete a full revolution of the crankshaft, as if the battery was dead. Even though it is the original battery I bought the car with, it still - when it NOW sees fit to do so - starts the car with one turn of the crank.

I live with a permanently intermittent <<P1AA2 Voltage Maintaining Device. Open Circuit Or Short Circuit To Earth Of The Supply Line Or Of The Earth Between The Voltage Retaining Device And The Power Storage Battery>> and whether this is live or not, when the car wants to start, it does.. My VIN is VF7**************[VIN obfuscated, can be read by forum staff] ...

When it fails, A battery reset (Pos lead removed for 30 seconds and replaced) allows the car to start. Battery voltage when it refuses, drops to 12.5V, and after reset returns to 12.7V.

I have carefully inspected all the negative power cables to and from the Ultra Capacitor and all connections are good and clean. I couldn't undo them, as the nuts/bolts are all a strange PSA size.

It sounds like time to replace the Voltage Retaining Device, and probably the battery, even though when in a good mood, it will start the car after being left standing for 5 or 6 days at the first turn of the crank.

I have been unsuccessful in finding any similar problem, so, please Administrators, point me in the right direction if this fault is well covered in any other Posts.

Regards
WillyR

[mickthemaverick]

Have a look at this thread which suggests an earthing problem, it includes the video linked below which shows you where the issue was.

[WillyR]

Thank you Mick,

I will have another go at the Negative Battery cable to the Start Stop Capacitor. Under the left hand side, the cabling is all clean, so I will check the under-bonnet part from the battery towards the SS.
I watched the post, and I didn't see how he got to the 10A fuse in the fuseboard next to the (RHD) glove box. Any ideas? I have just finished dismantling the Battery Protection unit, and all wiring is clean and tight. The main battery, at 15 years old is, I believe, requesting retirement, although, when the earth fault and start stop system don’t interfere, it starts at the first push of the START button.

Don't you just love it when cars misbehave....

[WillyR]

Can anyone help me with a cabling plan for the StopStart capacitor unit under the front left hand side wing of my car, please. There is a permanent 20kilohm resistance between the battery negative connector and the body negative point?

The battery negative cable is a dead short from the battery NEG Post to the end of the cable where it is bolted to the capacitor unit.

The car is my 2015 Citroen C4 Grand Picasso II B78 2.0 Bluehdi 150

Progress...?? Maybe

Regards
WillyR

[PaulC5]

How many miles has it done, could the starter motor have a fault ?

[WillyR]

Just under 90,000 miles. You could be right but it has never given any cause for me to suspect it. Thanks for the suggestion.

My latest check this evening shows a 20,000 Ohm resistance between the Battery Negative Post cable clamp and the Body Negative Post. The cable itself does not go directly to the Post, it goes to the Stop Start Capacitor Unit, and there is zero resistance between the Battery Negative Post Clamp and the cable end bolted to the Stop Start unit. Somewhere in the Capacitor unit there is a problem. Until I can find my way around it, I'm a bit stuck.