It’s not the fix all as the internet seems to suggest. If the car turns over fine in 99% of the time you can just ignore it. I say 99% because there is always an exception but I haven’t or seen one
First of the lead doesn’t just go from the battery to gearbox, there is a separate connection half way down going to the chassis rail
The part that connects to the gearbox carries huge amps to run the starter motor
Very little else uses this part of the cable, if enough amps can pass through it to turn over the engine over properly then you can pretty much guarantee it’s okay and there certainly enough to ground the few milliamperes of say a oil pressure switch.
Dirty, weak or loose connection to the chassis rail, half way down this cable will cause all sorts of weird problems. This part is very important. Pretty much every electrical component uses this the only exception I can think of is the power steering motor that has a separate lead to the battery terminal
Unlike the punto the cable itself rarely fails and all that is needed is a clean with a scouring pad, a bit of petroleum jell and bolting back
First of the lead doesn’t just go from the battery to gearbox, there is a separate connection half way down going to the chassis rail
The part that connects to the gearbox carries huge amps to run the starter motor
Very little else uses this part of the cable, if enough amps can pass through it to turn over the engine over properly then you can pretty much guarantee it’s okay and there certainly enough to ground the few milliamperes of say a oil pressure switch.
Dirty, weak or loose connection to the chassis rail, half way down this cable will cause all sorts of weird problems. This part is very important. Pretty much every electrical component uses this the only exception I can think of is the power steering motor that has a separate lead to the battery terminal
Unlike the punto the cable itself rarely fails and all that is needed is a clean with a scouring pad, a bit of petroleum jell and bolting back