Help needed

[Logikmaster]

Hi there, so after several years without issue my 156THP after being left standing for a few weeks decided to throw up a Engine Fault check message on the centre display yesterday, checked the codes and it’s P0070 & P0494 - then given the battery was slightly sluggish on first turnover I took it for a long run and the engine temperature gauge instead of being at 90 as it always is was reading only 50 ish and would rise up and then drop back again over the course of the journey….. in the past I’ve had some wild external temps showing on the screen like -40 but these always sorted themselves and no codes/engine warnings, so I’m thinking battery might be the cause but I tried clearing the codes but they return immediately upon restarting the engine…. Is there an issue with the coolant thermostat that is causing the issue (no leaks etc I can see) but not sure how that would affect ambient temp sensor? I did also get some weird messages flash up once yesterday about brake fluid low (which I know is ok as I checked it)
Not sure if I should go get a new battery fitted and see what happens or if there are other tests needing done before I spend money in the wrong place appreciate your thoughts

 

[Pedro]

P0494 Fan resistor poss low speed fault may need new relay
P0070 Ambient Air Temperature sensor circuit symptoms - EML light on Air con erratic-Engine temp sensor erratic signals being sent to the PCM trigger this code (Maybe thermostat issue which can disable the air con if faulty) also Air intake temp sensor can be open loop in the AAT sensor signal circuit & a short circuit in the sensor or a bad sensor need to check AAT wiring harness & connections unplug the sensor & test the terminals

 

[Logikmaster]

Thanks Pedro. Will get a look at these this week hopefully. Appreciate your reply