Electrical fault light - possible causes?

[timpootle]

I had a good vacuum out of the carbon dust and a good blow through with the air line. I also worked a small bottle brush up behind the brush ring to get rid of that Insulation fault lamp.

I reset the fault code with the Peugeot Test tool and the light went out.

John, is this a latching fault? I have seen my light go out and come back on while driving.

I have blown out the brush box, and washed it with isopropanol (Then blown it again and let it air dry before putting volts through it!) My light is still on.

I took the car to Earl Street Garage in Pretwich, and confirmed the fault as 'permanent fault - insulation'. They did not reset the fault. Thanks Martyn, Rick and A.J. for looking at it.

I will have another go at cleaning out the brush box, but I am running out of ideas. What exactly is the insulation fault light testing? Does anyone know?

[Flying John]

Hi Tim - it can be both a latched (memorised) fault as well as an on/off light.!.

Mine needed a reset using the Test box after the clean out and haven't seen it again. I guess tho if it had of come straight back on after the reset it would be a permanent insulation fault.


John

[EVan]

I will have another go at cleaning out the brush box, but I am running out of ideas. What exactly is the insulation fault light testing? Does anyone know?

It's measuring the voltage present on the chassis. There is an intentional reference voltage (50% of the pack voltage) applied to the chassis, and if the controller measures it deviating from that for a period of time, it will put the light on. You can measure this yourself using a volt meter, and you can disconnect parts (e.g. the motor field connection) to see where the fault lies.

Once the leakage is gone, the light will go out.

[Flying John]

Thats worthwhile knowing Evan. When I had the same thing there was lots of carbon around when I changed the brushes and after replacing the brushes, cleaning up and starting up, the light was still on. Using the test tool, which told me the fault light was on I used the option to reset and it went away and I havent seen it since.

John

[EVan]

Thats worthwhile knowing Evan. When I had the same thing there was lots of carbon around when I changed the brsuhes and after replacing the brushes, cleaning up and starting up, the light was still on. Using the test tool, which told me the fault light was on I used the option to reset and it went away and I havent seen it since.

Yes, it would probably have gone out itself after 20 minutes or so.

@Tim: Check also inside the terminal cover on the end of the motor, carbon dust can accumulate in there too.

[timpootle]

Thanks for the info, Evan. I will check the terminal box as soon as I can, probably Friday.

[timpootle]

I cleaned out the terminal box last Friday morning, as promised, and drove off to test out an Activa diagnostic computer.

The light was still on, but when I got up to John's house he was able to see, and clear, the insulation fault on his laptop.

Sadly, 2 miles down the road the light came on again, so I am now more confused than ever as to whether this fault is latching or not. Either way, I have more carbon sweeping to do.

Happily, we were able to scare John's 106 into health just by plugging the diag box in. This car has not moved since the return trip from it's MOT last year, just before our meet at the Manchester Science Museum.

[ChrisB]

Sadly, 2 miles down the road the light came on again, so I am now more confused than ever as to whether this fault is latching or not. Either way, I have more carbon sweeping to do..

Of course thats if its a motor insulation fault and its not leaking elsewhere, although a motor insulation fault is more likely.

You should be able to check the motor insulation using a 500v insulation tester, but you need to totally disconnect the motor before carrying out the tests, it would though prove if its the motor with the issue

ChrisB

[Grumpy-b]

I think that moisture ingress is a problem to a number of items in the control system. I have recently replaced some of the innards of the Temp sensor and all have shown oxidization of the copper cable that connects them to the loom. One item did not give a problem when in a test situation but did in the vehicle.

I would suggest that we give some thought to the items that do give errors and that can be the source of problems. Like the Battery mounted temp sensor that has a short lead to the sensor and a potential moisture ingress point.

There are also things like the deterioration of the gasket on the Brush cover, so gaskets and sealant neet to be replaced or used when resealing. Also on this point, a number of the covers I have taken off have had partially stripped threads, result you cant readily tighten them / make the covers seal properly, without using sealant.

I am just about to service a motor that is out of the Blingo and So I will pay good attention to point of potential failure and photograph them etc

Any movement on the idea of a resource page where we could put how tos and reference data.

Regards
Grumpy-b

[ChrisB]

Here we go again

Couple of days of rain and damp weather and "ta da" on comes my Fault light

Suspect its a insulation fault again

Trouble is it never dam well does it in the summer when I dont mind rumaging about, noooooo it has to be raining blowing a hoooowly and cold

ChrisB