Yes, you can set car and key memory with sss while enging is running, no problem at all. If you want to save gas, you can shut down the engine and turn the key to position 2 after SSS checking battery voltage.

You need to start the engine when the SSS prompt you that the voltage is too low, then shut down the engine and turn the key to position 2 when you see the SSS keeps to restart coding/programming without success when the engine is running. For encoding/programming DME, EGS and VTG, you have to shut down the engine and turn the key ot position 2 immediately when SSS starting to program/code the module, otherwise SSS will keep restart programming/coding without success. For other modules, you can keep the egine running during coding/programming without problem, but you will waste lots of gas. To save gas, just do what I said above for coding/programming DEM...

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--2004 E53 X5 4.8is - ECE version; right hand drive; Located in Hong Kong; ext. black sapphire metallic; int. leather black; adaptive dynamic bi-xenon headlights; 16:9 onboard monitor w/o navigation; 20" genuine BMW Y-spoke 214 wheels with Bridgestone Dueler H/P Sport tires; Int. rear view mirror w/ compass.