p38 electrical problem

[michaelp38]

i have a 1997 p38. it just wont start. by that it means that my starter motor doesnt crank, no power to the injector[coil pack. i took it to a range rover specialist and after few days working on it gave up. there is nothing wrong with the car computer. we took mine and place it in another car with my becm and my fuse box. the other car started. put the other car parts in my car. my car still wont start. there is a wire problem between the becm and the ecu. does anyone know what colour is the wire that send a signal from the becm to the ecu to start the car and what colour is the wire that bring the signal back if its a different one. please help as this is driving me insane.

[p38arover]

Did you try the other car's fuse box in your car?

[michaelp38]

yes i tried the other car fuse box, ecu and becm.
it is a loose wire that disconnect the communication between the ecu and the becm. i need to know the colour cause i think its pretty impossible to chase each and single wire

[bee utey]

Reading Rave for this model makes my head spin, but there's some truths which can be gleaned.

Most of the engine electrics (injectors, crank sensor etc) are powered by the brown/orange stripe wire from the main relay RL19. If this relay has failed then nothing is powered. It should be possible to manually earth this relay to make it power up. The earth is controlled by the ECM and BCM. My bet is on failed relays.

[michaelp38]

thanls but we replaced the fuse box and relays its not them. but i will trace this wire and check. anyone know the wire then send the signal rom the bcm to the ecu teling it to start the car ?

[adm333]

The BECM has an engine synch code with the engine ECU. If this code gets out of synch you will not start the car for love or money.

It needs to be reset using a faultmate or testbook etc.

When this happens the starter motor appears to be dead as it does not get any power at all.

Are you sure this is not the problem ?