| Hi Tony
I have a 2001 A170 and have start error fault on it. I too changed my battery and it was fine up until that point so i would have a guess that it is linked more to the battery change than your radio wiring. I have had mine in the dealers and it has CAN communication fault codes whch are different to yours but typically the fault went away when they had it. All the ignition lights come on but when the key is turned Start Error comes on and there is no cranking of the engine. Im still trying to fix this and believe it might be something to do with voltage spikes that have caused the fault with the electronics. If i disconnect the battery it sometimes goes away. If i find a solution ill let you know !! | 
