[Roger disco]

Hi I have an auto disco2 I did head gasket took a few days due to bits n bobs snapping
Battery disconnected for 5 days , when I tried to start fuel pump won't prime , she turns over but x and s lights flash when at position2 on ign and hazards go on
Nano com won't talk to ecu
Have tried all obvios stuff, had bcu out dry as a bone checked as many wires as I can figure out any ideas anyone please

 

[sierrafery]

....pump won't prime , she turns over but x and s lights flash when at position2 on ign and hazards go on

Charge the battery to full and check the inertia switch to not be unplugged/disturbed or tripped... the immobiliser has nothing to do with that cos immobilised = no crank

Nano com won't talk to ecu

to which ECU? did you try to access all of them and no comms at all?

 

[Roger disco]

Charged battery to full, checked and reset inertia switch then bridged to check,
Thing is it still cranks so only half dead? . So yeah not immobilised but sort of?
I'm not very clever with nano coming only learning but , it powers up but don't connect
.....

 

[Roger disco]

Oh maybe I should mention , I de aced it a little while ago but had no probs after that apart from the ace light being amber, would this affect it?

 

[sierrafery]

I'm not very clever with nano coming only learning but , it powers up but don't connect

did you try to connect it to SLABS or autobox ECU too and you get the same message? ACE has nothing to do with that...if the pump doesnt run are you sure is not dead? what if you bridge the pump relay? cand you hear it then?

 

[Roger disco]

Bridged relay and pump ran so no prob with pump.
I guessed ace would be OK, I'm trying to learn what the body control unit does it seems to do alot thought it might involve the ace too

 

[Roger disco]

I have finally got into slabs and the bcu
So no slabs action at all
But bcu is telling me stuff , like I'm moving gearstick from park to neutral but it says most stuff is off
I repaired the xyz switch a while ago and have had no probs with that since.
In bcu it mentions a W switch as well , what is this?
Also says inertia switch activated which I reset after the headgasket job and bridged it to noavail , when I put power to main relay fuel pump worked and ecu came on but obviously other side wasn't earthed . Could I just join the 2 smaller spades to earth it. I don't want to make anything worse!

 

[Roger disco]

In the bcu it said I only had 12.1 volts in battery but my multimeter says 12.6 volts?
I've put it on charge again.....

 

[sierrafery]

In bcu it mentions a W switch as well , what is this?

Part of it cos the it's full name is XYZW switch in reality (attached)

Also says inertia switch activated which I reset after the headgasket job and bridged it to noavail , when I put power to main relay fuel pump worked and ecu came on but obviously other side wasn't earthed . Could I just join the 2 smaller spades to earth it.

the inertia switch closes to power from F13 to relay's coil the ECU delivers the earth to main relay and the BCU gives earth to starter relay(cuts it when immobilised) so if you bridged the main relay and the pump started it's not immobilised, see "charging and starting" diagram or others HERE and check what's missing from the main relay's coil power or earth

 

[Roger disco]

It didn't start from inertia being bridged , I bridged the 2 bigger spades on the main relay , then fuel pump worked.but still activating M and S and hazards

 

[Roger disco]

It didn't start from inertia being bridged , I bridged the 2 bigger spades on the main relay , then fuel pump worked.but still activating M and S and hazards

I just understood what u meant then ill check thru that file.ta

 

[sierrafery]

You have to check in the main relay coil's cavities what's missing, the power or the earth to see why it's not closing on ignition and if it's missing the power it can be a problem in the fusebox if F13 is not blown eventually check if there is power from F13 to inertia switch's brown/black wire if you see what i mean

 

[Roger disco]

Yup got a 12.6 positive out of the feed to inertia switch and the fuse is good obviously
I've def got power coming in to main relay on 1 of the big spades when I joined that to the other 'big' spade ecu could be read and fuel pump ran (when key turned )
Should I get a positive signal at 1 of the small spades when ign is turned on

 

[sierrafery]

Should I get a positive signal at 1 of the small spades when ign is turned on

Yes, the power from F13 through the inertia switch one side and earth from ECU the other

 

[Roger disco]

Right I may have figured this out I just wanna check with u lot!
There is no continuity between white / green stripe wire coming from inertia switch , to either of the small spades on the main relay.
There is power at inertia switch and continuity..
So I believe I have a broken wire to the main relay , only thing I need to work out is which small spade should be connected to the inertia ,plug w+g.
I think it should be the 1 nearest engine .
I suppose I'll need to remove fuse box under bonnet to check.....? ...

 

[sierrafery]

I suppose I'll need to remove fuse box under bonnet to check.....? ...

Yes that would be the good move, then unplug C0605(maybe it's just bad contact in it) and check continuity from pin 3 to inertia switch, if interrupted rewire that one, if you have continuity the probem is within the fusebox, you must have continuity between the corresponding pin on the fusebox and relay's pin 86 cavity but better check in both coil cavities cos i've seen cases when the diagram was not accurate

 

[Roger disco]

I have problems identifying the plugs refered to by the numbers .... how does that system work?

 

[Roger disco]

Also as u said not all the wires in the diagrams are correct , which does your nut when not an expert.

 

[Roger disco]

I got the map of under box thanks at least those are clearly marked!

 

[sierrafery]

I have problems identifying the plugs refered to by the numbers .... how does that system work?

the connector views are from the pins/cavities side and for each pin there is the wire colour code... read the user guides in the diagrams file and HERE if you want troubleshoot yourself such things