Technical Description of OBD-II Trouble Code
The Exhaust Gas Recirculation Temperature Sensor B Circuit is experiencing intermittent or erratic behavior.
What does that mean?
This is a generic diagnostic trouble code (DTC) that is commonly found in OBD-II vehicles, including Mazda, VW, Audi, Mercedes Benz, Ford, Dodge, Ram, and others. The specific repair steps may vary depending on the year, make, model, and powertrain configuration of the vehicle.
Prior to the introduction of EGR (Exhaust Gas Recirculation) systems in the 1970s, engines would waste unburned fuel by expelling it into the atmosphere. Nowadays, vehicles must meet certain emission standards, which is where EGR systems come into play.
EGR systems help reduce emissions by recirculating fresh exhaust back into the engine to ensure efficient fuel burning. The EGR temperature sensor plays a crucial role in this process by monitoring the temperature within the EGR system and adjusting flow through the EGR valve. It accomplishes this using a temperature-sensitive resistor-type sensor.
If your OBD scan tool displays the code P041E and associated codes, it means that the ECM has detected a fault in the EGR temperature sensor or its circuits. It’s important to note that the exhaust system is hot, so caution should be exercised when working in this area.
The code P041E indicates an intermittent or erratic sensor reading in the EGR Temperature Sensor “B” circuit. Consult a vehicle-specific repair manual to determine which part of the circuit corresponds to “B” in your particular application.
What is the severity of this DTC?
The severity of this DTC can vary depending on the specific issue. However, it is not classified as severe since the entire EGR system was designed as an emission reduction strategy. That being said, exhaust leaks and defective EGR temperature sensors are not beneficial for your vehicle, so timely maintenance is recommended.
Here is an example of an EGR temperature sensor:
What are some of the symptoms of the code?
Symptoms of a P041E trouble code may include:
What are some of the common causes of the code?
Causes for this P041E engine code may include:
What are some P041E troubleshooting steps?
Basic Step #1
Start by visually inspecting the sensor and the surrounding EGR system, paying particular attention to exhaust leaks. Also, examine the sensor and its harness. Keep in mind the high temperatures involved, as they can damage plastic and rubber insulated wires. Thoroughly inspect all wiring for any signs of damage.
TIP: The presence of black soot may indicate an exhaust leak in the area.
Basic Step #2
Many EGR issues are caused by accumulated soot in the exhaust, which can result from poor maintenance or low-quality fuel. In this case, it may be beneficial to clean the EGR system or, at the very least, the temperature sensor. Note that sensors mounted within the exhaust system may be difficult to remove due to seizing. Applying a bit of heat using an Oxyacetylene torch (only for experienced individuals) can help loosen the sensor. Once removed, soak the sensor in carburetor cleaner or a similar product to remove soot. Use a wire brush to loosen any heavily accumulated soot. When reinstalling the clean sensor, apply anti-seize to the threads to prevent seizing.
NOTE: Be careful not to break the sensor inside the manifold/exhaust, as this can be an expensive mistake.
Basic Step #3
Verify the integrity of the sensor by measuring its actual electrical values against the manufacturer’s specified desired values. Use a multimeter and follow the manufacturer’s specific pin-out test procedures.
