Here goes got a c max1.8 2004

I've changed the battery,
checked voltage from alternator its charging at 14.1 volts running with everything on so i presume alternators ok

Changed aux belt so its not slipping

checked smart charge fuse F31 10a and replaced with a new one

taken off alternator 3 pin smart charge wire checked red one and getting 12.7 volts from batterty when not started

undone the 3 pin loom and checked for any breaks at plugetc got it right back to injector loom alls ok full continuity beeping on meter

checked and cleaned all earth wires and alternator main live all ok

Still the battery light comes up 20 seconds after starting up

Done the dash diagnostics and it seems code d900 is stored

it hasnt erased by hand held code reader

Has anyone any ideas where next to try

And where is the ecu on this car as i'll try and trace the blue and grey wires right back and check for continuity straight from ECU

I'm baffled now

cheers

 

I've got a 57 plate fiesta 1.6 diesel zetec s with exactly the same problem. Battery light comes on about 20 seconds after engine starts and all other things the same as you battery charging ect gave up in the end and just use it with the light on.

 

Seem to of fixed it, took the ECU out unplugged it checked smart charge wires for breaks with continuity meter none all good, cleaned up all visible earth points put all loom back took of negative lead run wire to positive to clear ecu memorys started it up no light 1 minute later up came light

took it for a long run to re set all values light went off and stayed off

So somewhere in that lot was the fix

Thanks for everyones help
johnkent is online now Report Post

 

Nope now alarms going off FFS

 

Oh mate what a nightmare modern electrics are