I know Jaguar requests to run IDS/SDD while key is on Ignition II but engine non running, and with a stabilised 60 Amps 13.6 Volt power supply connected to the battery.

But situations may arise when DTC's are logged hindering operation of the car, and when no external power supply is available to safely operate IDS/SDD with a VCM or a Mongoose.

If e.g. an ASF is triggered only because the compressor could not raise the car after two attemps in a very cold climate, and if a logged DTC then blocks any further operation of the compressor, the only way out will be calling the assistance...
While if the engine can be operated for some time and heat the engine bay (in particular the heads of the struts), there is a chance to succeed in raising the car later on if the code is cleared and the compressor can be reactivated.

So my question in the title, because the alternator itself can deliver a few tens of Amps at 14 V, that may allow to safely plug a current consuming VCM in the OBDII, acquire data and possibly clear codes.

 

Torque will clear most codes while the engine is running.
However if the code is still current it will come back

Cheers
34by151

 

I believe that voltage sag is a concern only when contemplating
programming. Clearing codes should only take a couple of minutes.

 

Generally you'll hinder IDS/SDD if you go around clearing codes (as its manuals say) but yes you can do it.

Can be a heck of an overkill tool just for that, though.

 

The ECM might not clear DTCs with engine running but the other modules should not care.

bob

 

Thank you all,

I agree that DTC's related to ECM would not be cleared while running the engine and that ongoing defaults would trigger DTC's back.
But it is good to know that DTC's could be managed this way, especially if the car is recovered with an ASF and a weak battery after being parked a couple of weeks during a harsh winter.

 

If those are the codes you want to clear maybe get a cheap elm327 and use with phone/tablet.

 

I understand from the answers that an elm327 may do it also.
I wanted to be sure that I could safely use my VCM/SDD setup to do so while the engine is running.
And the answer is yes, so I'm happy

 

Clear the codes on mine & others while running, but they will come back on after a while till fixed.

 

Not surprising, and fortunately!
But this can help in recovering from a "cold ASF" blockade

 

Sorry, I don't know