Altezzalink erratic ambient temperature

[L-Ken]

I have my is200 (2000 model) running on an altezzalink g4x ecu. As far as I can tell I've got all the in common bean functions working with the exception of the outside air temperature reading, this is occasionally close to accurate but will often spike up to 30-40 degrees (it's about 10 outside at the moment). Its not a big deal except it seems to effect the logic of the HVAC causing cold air when hot is desired etc. any help appreciated.

[Adamw]

Can you check GP Temp 1 runtime in the ECU next time it happens to see if this is also reading erratic.  I looked at the testing from the original engineer that reverse engineered this car and it looks like he has tested the BEAN messaging from -30°C to +50°C and I dont think any other user has reported an issue before so my suspicion at this stage is the issue is possibly on the input side - wiring/bad connection/sensor etc.  Or it could be the IS200 messages are different.

Do you ever get a fault code or CE light for AN Temp 3?

[L-Ken]

Thank you, can't believe didn't think to check that 🤦 yeah ecu is reporting the same temperature as the hvac, no fault code or cel light so messaging must be compatible. Will check the wiring and sensor, thanks again.