Sometimes you have to take your diagnostic process even further to get to the fix, as shown here. Having a scan tool with a multi-meter function allowed for the testing of the oil level sensor. See below to find out how.
Vehicle
2010 Hyundai i30 1.6 Diesel
Title
P250C, Replaced Engine Oil Level Sensor
Complaint
The customer states the check engine light is on.
Cause
Connected a scan tool and found code P250C – Engine Oil Level Sensor Circuit Low. Visually inspected the engine oil level on the vehicle’s dipstick and found the engine oil level was correct. Raised the vehicle on a hoist and removed the vehicle’s undertray to gain access to the engine oil level sensor. Used a multi-meter to check for voltage and ground at the engine oil level sensor connector and found both were present. Used a lab scope to backprobe the engine oil level sensor signal wire, drained the engine oil, and found the lab scope data did not change as the oil level decreased. Removed the engine oil level sensor from the engine and found no obvious faults. Used the multi-meter to measure the resistance of the engine oil level sensor while moving the sensor’s float and found the resistance measurement did not change. These tests verified the engine oil level sensor was faulty.
Correction
Replaced the engine oil level sensor, cleared codes, performed a road test, and verified the vehicle operated properly. The check engine light did not illuminate and no fault codes returned.