Codes 15 and 23

[calais_vn]

Gday
My engine light comes on about a minute after starting up, i did a diagnostic which revealed codes 15 and 23:

CODE 15 : The temperature seen by the ecm is below -35 degrees C
CODE 23 : MAT output more than 4.9volts, indicating manifold temp. less than
-35degrees c.

I'm thinking dodgy coolant and mat sensors? if not could someone please help me with getting rid off this engine light besides taking out the globe?

[89 vn]

Try takin out your fuse/discon the battery so the ecu can reset then after you restart the car check to see if any are gone which will help.
I had 4 codes a while ago and one of them was code 23 after a discon it went away and hasnt come back