D2 CAN system

**Tins** · 28th November 2025, 08:07 AM

Originally Posted by sierrafery

If the ECM learned the security code the engine should start and run, the CAN faults would send it to limp mode while driving not stop the engine running as long as the ECM has no fault though if you didnt unlock it with the fob after BCU replacement the ECM can still be immobilised unless the passive immobiliser was disabled... you can't replicate the CAN faults without a running engine or the faults will be current as long as the engine doesnt start for some reason so better get the engine running first then go further

P.S. I just realised that there is a too cryptic statement in those fault descriptions i attached few posts ago as they should have said :"ignition to be switched on whilst fault not present and engine STARTED" instead of "cranked"

Hmm.. So clearing the faults with the Nanocom won't actually clear them as they are logged? Is that what you mean, sort of? So, I'm possibly back to the CPS as the cause of it not starting now, maybe. I'm going to test this with my oscilloscope, and also the wiring to it which I renewed.

Ok, so when I renewed the CPS wiring ( the car has run since, BTW ), I inspected the wiring to the red plug end. The RAVE pic shows pin 16 as being unpopulated, but mine had a black wire in it ( pretty sure it was black, there wasn't much left as it was maybe 10 cm long ). RAVE also shows, in the engine management diagram, that pin 16 has something going to it, represented by a dotted line. I guessed that the shielding on the CPS would have terminated there, and so I attached it there. The old CPS wiring, pink/black and white/blue had been butchered a number of times before, and was also very brittle. Pin 16 was not blocked off with a plug like other unpopulated one are.

Screenshot 2025-11-28 at 8.47.06?am.jpg

The car stopped where it is when the CPS fell to bits. I replaced it with a spare. Started once and not a second time. As I have said, I have been down a number of rabbit holes because I have been sidelined by the other issues, not least the immobilisation. So, back to basics. Check the wiring to the the CPS again, and the CPS itself. I can ignore the CAN errors until it starts? This has been putting the blinkers on my thinking, as it all seemed related as it all appeared at the same time, roughly.

Screenshot 2025-11-28 at 8.45.02?am.jpg

By the time I'm done I will have rewired the entire car

**sierrafery** · 28th November 2025, 08:19 AM

For the CPS just watch nanocom on instrument or fuelling mode for rpm while cranking, if you get above 250rpm the problem is not that but it's wiring's shiled must be connected to pin 16 otherwise the signal can be mixed up by the starter motor's electromagnetic noise induced in the main wires... yes work on the CAN fauts after the engine is running, they might dissapear after you reset addaptive values

**Tins** · 28th November 2025, 04:32 PM

Nanocom showed zero rpm on one, intermittent 224 on the other. Bought a new one, came home and fitted it, and the buttonon the key fob fell off. So, whenI stop seeing red I'll go and solder it back on... D1 looks better every day.

**johnp38** · 28th November 2025, 06:22 PM

Originally Posted by Tins

Nanocom showed zero rpm on one, intermittent 224 on the other. Bought a new one, came home and fitted it, and the buttonon the key fob fell off. So, whenI stop seeing red I'll go and solder it back on... D1 looks better every day.

When I was rewiring my crank sensor I kept reading about a washer/spacer that keeps it from being too close and getting touched by the flywheel, mine didn't have a spacer and I don't think I did anything about it but maybe some need to be clearanced and some don't ?

Just a thought, maybe shack or fery can chime in I didn't pay it any attention at the time. Maybe that's why I get those spikes in my nanocom logs, who knows...

**shack** · 28th November 2025, 06:28 PM

Originally Posted by johnp38

When I was rewiring my crank sensor I kept reading about a washer/spacer that keeps it from being too close and getting touched by the flywheel, mine didn't have a spacer and I don't think I did anything about it but maybe some need to be clearanced and some don't ?

Just a thought, maybe shack or fery can chime in I didn't pay it any attention at the time. Maybe that's why I get those spikes in my nanocom logs, who knows...

You get spikes in the Nanocom logs because of the Nanocom. I've never seen it in my logging gear.

As far as the spacer goes, yes, some need a spacer for clearance, from what I can remember it was a "cure" for "noisy crank signal" faults.

There will be an air gap listed somewhere, but I have no idea what it is.

I have put a spacer on one once for the "noisy" error, from memory it didn't fix it, but a new starter did.

**sierrafery** · 28th November 2025, 06:51 PM

Originally Posted by shack

You get spikes in the Nanocom logs because of the Nanocom....

I didnt know about such issue, i've used nanocom many times on live instrument mode to check rpm while cranking on no starters or at idle and can't say that, it's quite steady, maybe in long saved logs there can be rare and random spikes but it happens for any reading from time to time. What i know is that a rpm 250+ reading while cranking is needed to start well.

the noisy crank signal is always triggered by the starter's(or some other) elecromagnetic noise but not the case when the vehicle stops while driving as the starter is not energised then also the noise won't stop a running engine just not let it start.

I know nothing about the CPS shim, iirc mine doesnt have one unless it was stuck to the hole and i didnt even observe it

**Reddirt204** · 29th November 2025, 10:20 AM

Originally Posted by shack

You get spikes in the Nanocom logs because of the Nanocom. I've never seen it in my logging gear.

As far as the spacer goes, yes, some need a spacer for clearance, from what I can remember it was a "cure" for "noisy crank signal" faults.

There will be an air gap listed somewhere, but I have no idea what it is.

I have put a spacer on one once for the "noisy" error, from memory it didn't fix it, but a new starter did.

Interesting, I'm getting the "noisy" error constantly (I can clear it when running and it stays clear) I've changed sensors but still the same, I'll try the washer to see it that's the solution

Cheers

Redd

**shack** · 29th November 2025, 12:03 PM

Originally Posted by Reddirt204

Interesting, I'm getting the "noisy" error constantly (I can clear it when running and it stays clear) I've changed sensors but still the same, I'll try the washer to see it that's the solution

Cheers

Redd

I think you've already got the answer!

If you have a starter that seems to Labour a bit or sounds unusual, that's the normal culprit.

The fact the fault doesn't come back until restart, ID'S the starter pretty well.

If it's starting fine it's not a big concern,(the "noise" interferes with the CPS signal), if it's hard to start you may need to do something.

**Reddirt204** · 29th November 2025, 04:41 PM

Originally Posted by shack

I think you've already got the answer!

If you have a starter that seems to Labour a bit or sounds unusual, that's the normal culprit.

The fact the fault doesn't come back until restart, ID'S the starter pretty well.

If it's starting fine it's not a big concern,(the "noise" interferes with the CPS signal), if it's hard to start you may need to do something.

Thanks Shack,

It starts like a champ every time (except when the non return valve gave out and had sat for 2 weeks at the airport) so I'll just leave it alone,

Sorry about the thread drift, we can now return to normal programing....

Cheers

Redd

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