P38A engine ecu

hi i have a 2000 diesel p38 which has refused to start since last winter.
finally got it going today thanks to a thread which mentioned running an earth wire from the engine ecu (behind the battery)
my question is this. before i encountered the starting fault no wire was required and now it seems indispensible.
can anyone help me understand why?
thanks

Sounds like a bad earth somewhere to me

kermit_rr said:

Sounds like a bad earth somewhere to me

Click to expand...

+1 check the earth point on the inner wing under the front of the fuse box.

southby said:

hi i have a 2000 diesel p38 which has refused to start since last winter.
finally got it going today thanks to a thread which mentioned running an earth wire from the engine ecu (behind the battery)
my question is this. before i encountered the starting fault no wire was required and now it seems indispensible.
can anyone help me understand why?
thanks

Click to expand...

As others have said it's due to an earth fault. I suspect however it may be internal to the ECU. I have read of this mod being needed a few times but never heard of a resolution that allowed the extra earth wire to be removed. Make sure your earth wire is of a good size and leave it in place.

southby said:

hi i have a 2000 diesel p38 which has refused to start since last winter.
finally got it going today thanks to a thread which mentioned running an earth wire from the engine ecu (behind the battery)
my question is this. before i encountered the starting fault no wire was required and now it seems indispensible.
can anyone help me understand why?
thanks

Click to expand...

Try bridging the fuel pump relay also to make sure you have a supply from the tank.
Glow plugs also.
You can check the earth's for continuity between the
battery /chassis,
chassis/engine,
engine/battery.
Do the same for the live wire.
Battery/starter,
Starter/alternator,
Alternator/battery.
This will help confirm any doubt of power and ground before actually removing stuff if not needed and saving you time.

thanks to all for the feedback
will be sure to beef up the new earth
one other thing which was noted was the nanocom was unable to communicate via the obd
now all is restored