PROFSR G wrote:

Hi Gary,

No I'd say the DC/DC voltage outputs look correct to me, (typically 55v to 68v) or thereabouts.
Pedal pos sensors 1 & 2 both look to be in range to my eyes (@ 0% throttle) but the readings at full throttle should be looked at to confirm. (4.00v ps1, 2.00 v ps2)

The thing is the OP has posted a huge amount of data here, all of which takes a lot of time to crunch! And then it may not even be relevant, thus proving utterly fruitless!
It's better to focus on a few systems at a time and work through them. This way you have a better chance of taking potential contributors with you and "in the game"!!

I would respectfully suggest the OP needs to start with the basic stuff if he hasn't already done so. (Sorry I couldn't spend the time to read the entire thread) Start with what you know which in this case "seems" to be a temperature related incident/error.
So, as a starting point look at live values for the engine/transmission, selecting the temp values and see what's going on there as the test drive reaches full temp. Try to stress the problem on the test run by varying driving style and hopefully provoke a component dtc other than just a COMS error! This might give some direction in which to focus with the diagnostics!
If there is nothing meaningful from that, then move on to power supply (Alt, earths, Batt etc) and after that on to the wiring plugs of the suspected components like the TCM, transfer box loom plugs, etc.

There might something in what you say regarding either power supply or earthing, and these should be scrupulously interrogated. BUT, on the surface this to me seems to be a COMS issue, and so I'd be looking closer at the CAN BUS cabling/connectors to the IID signalled components.

The MM test should be on DC volts not AC

Hi mate

Bless u for having a look, very grateful , was also thinking that seeing it’s not coming up with a hard DTC , great call ref live data monitoring sensors etc

Indeed that’s what I thought ref earths where maybe a signal is going back but not a good one so maybe it’s just below what it should be , not enough to trigger a hard DTC but a soft U comms error

Got to love em, lol

Ref the mm, seen where it says to test an alternators diode is to set the mm to AC and should be below 0.5 volts

Edit, just looked back at the link , ref


3. Checking for a Bad Diode

Usually, a bad alternator diode will cause your headlights or instrument panel lights to flicker or dim and, sometimes, drain battery power overnight, or in minutes.

* To check for a possible bad alternator diode, switch your voltmeter to a low setting on the AC (alternating current) voltage scale.
* With the engine running, touch the meter probes to the battery terminals.
* Your voltmeter should read 0 AC volts.

Any amount of AC voltage would indicate a bad diode, so you'll need to replace the alternator.

https://axleaddict.com/auto-repair/Alterna...stem-Tests

was just curious and Hands up know I’m guilty of getting confused regarding where the decimal point is with some readings

Am wondering if a trip to halfords may be worth it in order for it to be checked out with an oscilloscope

Thks again my friend

  

TyphoonDisco wrote:

Hi,

Thank you, I did have a look at this previously and it looked to be in quite an exposed position, not the best place for electrics! There are 2 large block connectors with sliding locks which hold the male/female parts together. Are these the 2 you refer to?

The connections/pins looked clean as a whistle but I wonder if one of the wires has frayed.

Today I am going to check those 2 connectors again, give all the cables a wiggle to see if that causes the issue and also check the wiring in the passenger door sill area.

After that I think it's time to get into end to end testing for continuity issues. I've no idea how to do this so it will be over to the experts!

Hi buddy

Just had a thought , if I have a halfords etc near u that could do a full diagnostics on ur alternator to rule it out

Ref continuity, disconnect battery and do the same as u did with an earth lead, ie meter into continuity , one test probe on one end of the wire u wish to test and other test probe on the other end of the wire

Indeed the one near the near side rear wheel

Also know ur not daft , plse, plse don’t ever be tempted get under the disco without axle stands

Also check the connectors behind the headlights , moved from the front wheel arch after 2007 I believe

Plse let us know how u get on and there’s always help here so don’t think ur on ur own

  

gstuart wrote:

PROFSR G wrote:

The MM test should be on DC volts not AC

Ref the mm, seen where it says to test an alternators diode is to set the mm to AC and should be below 0.5 volts

Sorry Gary I misunderstood and thought you were reading the output voltage.

AC for the diode, DC for the rectified side

 yµ (idµ - eAµ) ψ=mψ

 

TyphoonDisco wrote:

Hi,

Thank you, I did have a look at this previously and it looked to be in quite an exposed position, not the best place for electrics! There are 2 large block connectors with sliding locks which hold the male/female parts together. Are these the 2 you refer to?

The connections/pins looked clean as a whistle but I wonder if one of the wires has frayed.

Today I am going to check those 2 connectors again, give all the cables a wiggle to see if that causes the issue and also check the wiring in the passenger door sill area.

After that I think it's time to get into end to end testing for continuity issues. I've no idea how to do this so it will be over to the experts!

 yµ (idµ - eAµ) ψ=mψ

 

PROFSR G wrote:

gstuart wrote:

PROFSR G wrote:

The MM test should be on DC volts not AC

Ref the mm, seen where it says to test an alternators diode is to set the mm to AC and should be below 0.5 volts

Sorry Gary I misunderstood and thought you were reading the output voltage.

AC for the diode, DC for the rectified side

I’ll forgive u just this once , Next time it’s the tower for u

Takes cover

Still curious about that alternator if it’s causing a spike through the relay and then triggering the faults through the other ecu’s in the canbus

  

TyphoonDisco wrote:

Hi,

It's been another long day under the car.

I've removed the NSR wheel and arch and inspected the 2 blocks. Although they were caked in dried mud/dirt, there doesn't seem to be any signs of damage, the internals of the connectors look clean and dry and no amount of wiggling would cause the fault to come on.

I've also examined every connector under the bonnet, including behind the nearside headlight. Lots of wiggling/disconnecting of everything but couldn't find any signs of corrosion/split wiring/damaged sheathing or anything that could get the fault to occur.

I have tried a few diagnostics using the MM. I tried testing the volts AC at the battery terminals with just the ignition on then with the engine running.

With just the ignition on I get 0.001vAC but every so often it just flickers up to approx 0.006 to 0.008vAC and then returns to 0.001vAC.

With the engine running it sits at approx 0.013vAC and then every so often it will flicker up to 0.088 to 0.100vAC.

If you'll remember in one of my earliest posts, when the car is idling I sometimes get a little change in audio as if the car is slightly labouring. It's not perfectly regular so I can't forecast when it will happen but I'd say once every 5-10 seconds. What I've seen with the above is that this slight change in engine note is often accompanied by a minor spike in vAC across the battery terminals.

In addition, when sat with just the ignition on waiting for the fault to arise it tends to come on just after one of the regular clicks of RELAY 6 which happen every 15-16 seconds.

In summary, it seems like there's a regulation/voltage issue somewhere. There's definitely something not happy with RELAY 6 and I think the issue is eventually dragging down the electrical to the point where the CANBUS has a hissy fit.

Hope my random blurb makes sense!