the ****

Well worth checking the main engine compartment fusebox out-fairly common fault with P38's and can be confused with BECM problems. Pull all the fuses & relays out and have a look for traces of burning around the fuse/ relay sockets, also bury your nose in there for traces of burning smells. From memory, new fuse box is around £100-tread carefully if you are thinking of replacing it with second hand.
Good luck-keep us posted................

Like Irish said, check the engine fuse box, specifically also check F33 - should be a 5 amp fuse - this is the power supply to the diagnostic socket and can cause trouble for diagnostic machines if its blown.

When you say the computers would not connect, what exactly happened?? Was he able to communicate with ANY of the ECU's at ALL?? If none of the ECU's communicated with his machine how did he know the BeCM was ok??

Another problem can be the OBD socket itself - I take it you saw where he plugged in?? Get down there and just drop the panel down, tis only held in with a few of those plastic screw type fasteners. Once its dropped pop the OBD connector out of the panel itself and then get a bright torch and inspect the socket closely, the pins on the socket can get damaged sometimes and they can also spread out too much as well meaning no communications to some or all ECU's.

What were the 'several different things' he tried to get it to work??

Assuming the OBD socket itself is ok then the next step I would take if I didn't have any diagnostic equipment of my own would be to use the ETM in RAVE and trace the connections from the plug back to their respective sources. Have you got RAVE??

-Wills

EDIT - Done a little research and sat with the ETM myself for a good half an hour, when checking the under-bonnet fusebox, as stated, check for corrosion, damage etc but also make sure you double check F26 (20amp) as well as this supplies the power to the engine ECU. If you think the fusebox checks out ok then you will need to move onto tracing the wires like I said above I reckon.

The way I understand it, reading the ETM, is that it works like this...

turn the ignition on, a mobilise signal is sent from the BeCM via pin 5 of connector C112 (black wire) to the engine ECU - this passes through C106A/C506A on pin 1 until finally reaching the ECU via C507 on pin 26

Assuming everything is ok the engine ECU responds back via pin 22 of connector C507 (black wire with a yellow stripe) to the BeCM - this signal passes back through C106A/C506A on pin 4 and then reaches the BeCM at connector C114 on pin 5.

Once the signal is received the BeCM then switches on the check engine light - If all that's not right someone please feel free to jump in and correct me!

Sooooooooooooooooo, it is probably also worthwhile checking out the connectors I talked about above as well, look closely for any corrosion or damage to them.

ok wills,he plugged in p/s foot well,said it was communicating with the one under seat but could not get them to talk to each other(ecu under bonnet) he then checked fuses /drivers seat,then fuses under bonnet ,at the same time on his Mobile talking to his mech trying to trace the fault,he did find that the (engine check)relay had no earth ? so i will have a look at f/box first,

hi again ,haven't had any luck with f/box and the weather is against me, and now I'm back in work (thank f***) but having to work away from home,so the old girl is for sale has is ,shame she was very good till this problem,will take some pic and put in the f/sales when i get home,any one interested let me know

Pity because if it is the fusebox (Suspect), then the fault could lose you more than the £100 for the new fusebox on the selling price & trade prices for P38's aint that good at the moment.

now working away,so shes for sale as is,pity she was really good before this happened will post in f/sales before ebay,any one interested let me know may swop why

hi all home again,so will be looking in to problems again first a better look at f/box , did put batt back on today,dash shows disabled and wont take key code, so cant sell it as is ,next step get her going and keep her.:doh:

update ,had thep38 taken to a garage james tennent near okhampton put in a s/hand fuse box and had to replace wire ? from bcm under d/seat to fuse box and now starts every time pick it up tomrow thus 12th hope all ok give you more info asap.wills and irish you were spot thanks very much.

Thanks very much for the update Pete-that's what the forum is all about-providing a starting point for others. Glad you are sorted.:bolt: