Code 41 is the heater circuit of the primary oxygen sensor.

What year/model? Often that sensor is mounted in the exhaust manifold right up front. Unplug it, look for the 2 same-color wires from the sensor. Measure resistance between them - it should be 10 to 40 ohms. If not, get a new sensor. If the resistance is OK, then post back about checking the rest of that circuit.