2006 Range rover non-start / comms issue

[WRX 14]

Hi guys, have a problem with a 2006 Range rover (Registered 2007) with the 3.0 M57 BMW engine.

Car will crank but not start. (well, maybe 1 time in 100 can get it to fire briefly for a few minutes - and after around 30 sec running the brake lights come on themselves). Customer reported that when they started having problems they were driving the car and lost throttle and engine would continue to run.

Tried to access comms via OBD using Snap-On verdict however its only connecting with the instrument cluster, heater controls and ride level control with no codes..
i've scoped the can-bus wiring at ECU and ABS, and the signal trace is bad (see attached photo). Scoped can bus at OBD plug and is normal - guessing there are separate CAN busses in the car. CAN-Bus resistance measured good at around 60.1 ohms at the ECU & ABS.
All fuses ok.

When the ignition is turned on, only the airbag light does its short cycle.
Another thing i noticed is with only ignition on there is no brake lights visible (works ok if press brake pedal), but when connect my GYS battery support the brake lights come on. Initially i suspected maybe there was an internal issue with the ABS, and when i disconnect the ABS module plug the brake lights go out (lights still work when press brake pedal) however no difference in comms and still no start.

Had only gone and had a quick look over the car and currently sorting out some wiring diagrams to help aid delving father into the issue, however if anyone has seen a CAN-bus trace similar or car doing something something like this in the past and has any pointers it would be greatly appreciated.

Never seen CAN trace like this, so not sure if its a bad module corrupting the data on network, or corrosion problem etc..
Beginning to think i'm going to have to strip half the car to access all modules on this network to disconnect them and scope the bus .

[autoden]

That trace look bad to me. Try to unplug the frm they are easy to access and cheap to repair. Have a look at bellow screen for a swimming pool.

[autotrans]

Possibly bad ground, wondered if it worth trying a small capacitor (micro-f) between can lo and ground to clean the trace up a bit.

[WRX 14]

Thanks, Is the FRM the module the one behind driver kick panel?

[WRX 14]

Possibly bad ground, wondered if it worth trying a small capacitor (micro-f) between can lo and ground to clean the trace up a bit.

Thanks.
I presume then that if I fit a small capacitor and it clears u0 the trace enough that it should allow commas again, and this would indicate i’m Looking for a wiring fault as opposed to a faulty module?

[autoden]

Unplug one of the sensors on the engine and be sure you have a 5v reference. See if a bad module is pulling it down. Unplug the foot well module behind kick panel, because the brake light and others run through it. Once unplugged see if you have comms.

[Dunker]

Could be water has got in somewhere. Something's screwing with CAN-low. Could be anywhere. Check for green death. Maybe in back of car somewhere. If it's not obvious water ingress unplug all modules one at a time till signal clears.

[Meat-Head]

ON TOPIC:-

VAUGUE MODE ON:-

1) Years ago when these were spanking new looked at one, non start
was ‘blown fuse’ somewhere near passenger headlights

2) Not fully sure details but ‘common fault - passenger seat’
Wiring to back

VAUGE MODE OFF:-

[Meat-Head]

OFF TOPIC:-

*HATE* editing posts

ON TOPICS:-

A) car has sunroof?

https://m.youtube.com/watch?v=KkCHe7PEu_g

B) trunk lefthand side, audio amp full of water?

OFF TOPIC:-

google range rover fire. Common features