LN3 Computer/s **** itself

[AlphaOne36]

G'day,
My 04 VY has recently started having computer issues. Everytime the car hits 82 degrees (I have an aftermarket engine guard which just reads temp of engine) the ABS fault warning, check engine, and service error - contact retailer warnings come on. As well as this I lose the gear selector icons in the dash, the dash temp gauge stops working, the a/c stops working, and the car idles just above stall (>500rpm). If I continue to drive for a bit this all resets and the car goes back to normal. I went and got the codes read and here's what it's reading:
BCM:
- 18 Auxiliary Serial Data Bus Fault
-02 Slip Ring Failure
-07 PCM data lost
-26 ABS data lost
ECM:
-P0506 Idle Speed Error
-P1255 Theft Deterrent Signal Missing (This could be because I have an aftermarket display instead of the stock radio)
-P0131 Right Hand Oxygen Sensor Signal Voltage Low
-P1064 Low Speed Fan No BCM Response
-P0530 A/C Refrigerant Pressure Sensor Circuit Malfunction
-P1571 Requested Torque Outputs Of Range
Instrument:
-18 ECC fault logged

Some things that could be noteworthy:
New Battery, second hand alternator (already ordered another one this is just a placeholder), Lpg, After codes were cleared did try removing temp monitor (engine guard) and still occurred.

Engine Guard is this:
https://engineguard.com.au/

Any help is appreciated as this is my first car with computers

 

[lout]

how are you measuring the 82 degrees
what is this engine guard
has this car been "tuned"

 

[AlphaOne36]

how are you measuring the 82 degrees
what is this engine guard
has this car been "tuned"

Engine guard is just an actual temp reader, measures temp of coolant in and out. No the car hasn't been tuned in anyway since factory I believe. I'm giving it to my mother so stock is more than enough power

 

[AlphaOne36]

Update: Just changed alternator over and still doing, anyone got any ideas?

 

[UTE042_NZ]

Where is the engine guard / temperature gauge drawing power from?
Have you tried disconnecting that to see if the issue persists (after clearing the fault codes)?
Have you checked that guard's wiring for shorts? (Strange that it always happens at 82˚, what is the resistance of the temp sender at that temperature?)

 

[Immortality]

Ok I'm having a blond moment, L63?

 

[AlphaOne36]

Where is the engine guard / temperature gauge drawing power from?
Have you tried disconnecting that to see if the issue persists (after clearing the fault codes)?
Have you checked that guard's wiring for shorts? (Strange that it always happens at 82˚, what is the resistance of the temp sender at that temperature?)

Yeah first thought was disconnecting the engine guard, didn't change it at all. I disconnected it, then the next day ran it for a bit still occurred hence my lack of investigation further into the engine guard. The wiring Is brand new and is only two wires hooked up to the waterpump and the other is on the thermostat. It draws power from the fuse under the steeringwheel switches on with aux, it's just pushed into an empty fuse.

 

[AlphaOne36]

Ok I'm having a blond moment, L63?

L63 is just the 3.8L V6 in the vy

 

[Immortality]

OK. L36 not L63.

Thread title changed.

 

[AlphaOne36]

OK. L36 not L63.

Thread title changed.

Just googled and it seems L36 is correct and that's the engine in it, I'm new to commies so my apologies for confusion