Got a fault on my 2006 L320 2.7 where 30 seconds after starting, get a transmission fault error, all the gauges and screen go dead, charging light comes on but engine keeps running. If switched off and left overnight, the battery is beyond dead next morning, reading ~8v. Fully charging the (only 1 year old) battery starts it fine and the same thing happens. I found some broken wires behind the battery and repaired those properly and re-wrapped the loom in cloth tape but no difference. I suspect the Trans fault is just a symptom, could this be alternator related? I took off the belt and the alternator feels fine but the bearings could be good and the diode failed I suppose. Gap IID codes are below, the EPB module contact one has been there since I got it a year ago and EPB works fine, I also know about the EGR one but those high voltage and generator ones are new. Any pointers on where to look next much appreciated.

VIN SALLSAA136A943455
Model L320 - Range Rover Sport 2006
Vehicle scanned on 14 May 2025 19:50:50
IIDControl 4.2.11 Build 168 Android - IIDTool BT V4.0 B3998

Airbag

B00DF-00 - Passenger restraints disable switch (AE)
( on 06-10-2028 14:14:43 at 128308 mi )

B1A00-17 - Control module - General electrical failure - circuit voltage above threshold (2E)
( on 06-10-2028 14:16:10 at 128308 mi )

Audio System

U2003-86 - Fibre optic communication bus - Bus signal/message failure - signal is invalid (2B)
( on 06-10-2028 14:28:53 at 128308 mi )

Body Control

U2001-68 - Reduced system function - Algorithm based failure - event information (2F)
( on 06-10-2028 14:16:26 at 128306 mi )

Engine TDV6

U0128-00 - Lost communication with parking brake control module (2F)

P140D-00 - Exhaust gas recirculation control circuit B range/performance (2F)

P1934-00 - Vehicle speed signal (2F)

P0563-00 - System voltage high (2C)

P0625-00 - Generator field terminal - circuit low (2F)

Instrument Pack

U0128-87 - Lost communication with parking brake control module - Bus signal/message failure - missing a message (2E)

Suspension

U0128-87 - Lost communication with parking brake control module - Bus signal/message failure - missing a message (2F)
( on 06-10-2028 14:14:50 at 128308 mi )

Transfer Case

P0563-00 - System voltage high (2F)
( on 06-10-2028 14:16:05 at 128308 mi )

U0128-87 - Lost communication with parking brake control module - Bus signal/message failure - missing a message (2E)
( on 06-10-2028 14:14:50 at 128308 mi )

U0122-87 - Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message (2E)
( on 06-10-2028 14:15:56 at 128308 mi )

Transmission

U0128-87 - Lost communication with parking brake control module - Bus signal/message failure - missing a message (2F)
( on 06-10-2028 14:14:48 at 128308 mi )

P0563-00 - System voltage high (AF)
( on 06-10-2028 14:15:56 at 128308 mi )

P0500-00 - Vehicle speed sensor A (2F)
( on 06-10-2028 14:16:01 at 128308 mi )

Vehicle Dynamic

C1A00-17 - Control module - General electrical failure - circuit voltage above threshold (0B)
( on 06-10-2028 14:15:56 at 128308 mi )

U0128-87 - Lost communication with parking brake control module - Bus signal/message failure - missing a message (0B)
( on 06-10-2028 14:25:03 at 128308 mi )

Ventilation

B1B74-00 - Front foot-defrost mode stepper actuator (2F)
( on 06-10-2028 14:16:01 at 128308 mi )

B1B75-00 - Front foot-face mode stepper actuator (2F)
( on 06-10-2028 14:16:01 at 128308 mi )

B1B76-00 - Front left air blend stepper actuator (2F)
( on 06-10-2028 14:16:01 at 128308 mi )

B1B77-00 - Front right air blend stepper actuator (2F)
( on 06-10-2028 14:16:01 at 128308 mi )

B1B78-84 - System pressure - Bus signal/message failure - signal is below allowable range (2F)
( on 06-10-2028 14:14:46 at 128308 mi )

I changed the alternator and that fixed everything. Worth noting that what appears to be a torrent of failures was simply due to an alternator with failed diode/voltage regulator.