Sensors are not immortal. The EGT sensor is exposed to exhaust temperatures that can exceed 800°C (1472°F). Eventually, the internal thermistor fails, or the sensor tip becomes coated in soot/carbon, rendering it unable to read temperature accurately.
Yes, indirectly. A weak or failing battery can cause low system voltage, triggering false relay circuit codes. Always test battery voltage (should be 12.4V+ key off, 14.2V+ running) before deeper diagnosis. code 54 cruze
Raise the vehicle safely. Locate the EGT sensor #2. On the 1.4L Cruze, it is typically screwed into the downpipe, just below the Sensors are not immortal