Technical Description of OBD-II Trouble Code
The engine exhaust temperature is too low during cold start.
What does that mean?
This generic powertrain diagnostic trouble code (DTC) is applicable to many OBD-II vehicles, including Ford (Mustang, Escape, EcoBoost, etc.), Dodge, Jeep, Land Rover, Nissan, VW, etc.
When the code P050E is stored, it indicates that the powertrain control module (PCM) has detected an exhaust temperature below the minimum threshold during cold start. Cold start refers to a drivability strategy used when the engine is at or below ambient temperature.
In my professional experience, exhaust temperature is only monitored in vehicles equipped with clean burning diesel propulsion systems.
This code is more commonly found in geographic locations with extremely cold climates.
Changes in exhaust temperature are crucial for reducing emissions in modern clean burning diesel engines. The PCM must monitor exhaust temperature to ensure that the necessary actions are taken to achieve these significant temperature changes.
Diesel exhaust fluid (DEF) injection systems are responsible for introducing DEF into the catalytic converter and other parts of the exhaust system. These DEF mixtures generate the increased exhaust temperatures required to burn harmful hydrocarbons and nitrogen dioxide particles trapped in the exhaust system. The PCM controls the DEF injection system.
During engine cold start, the exhaust temperature should be at or near ambient temperature. If the PCM detects that the exhaust temperature is lower than ambient temperature, it will store the code P050E and may illuminate a malfunction indicator lamp (MIL). In most cases, multiple failures are required for MIL illumination.
Cold car:
What is the severity of this DTC?
When the code P050E is stored, DEF injection is likely to be disabled. This code should be considered severe and addressed urgently.
What are some of the symptoms of the code?
Symptoms of a P050E engine code may include:
What are some of the common causes of the code?
Possible causes for this code may include:
What are some P050E troubleshooting steps?
I would start the diagnosis by searching for relevant technical service bulletins (TSB). If I find one that matches the vehicle I am working on, the exhibited symptoms, and the stored codes, it is likely to help me accurately and quickly diagnose the P055E.
To diagnose this code, I will need a diagnostic scanner, an infrared thermometer with a laser pointer, a digital volt/ohmmeter (DVOM), and a reliable source of vehicle information.
The vehicle information source will provide me with diagnostic flow charts for the P055E, wiring diagrams, connector face views, connector pin-out charts, and component testing procedures/specifications. This information will be crucial in reaching an accurate diagnosis.
After visually inspecting the exhaust temperature sensor wiring and connectors (with a focus on wiring near high-temperature areas), I would connect the scanner to the vehicle diagnostic port and retrieve all stored codes and relevant data. The code data from the scanner may be helpful later in the diagnosis. I would write it down and keep it in a safe place. Next, I would clear the codes and test-drive the vehicle (during cold start) to see if the code is reset. The test-drive should also displace any previously trapped moisture in the exhaust system.
Use the DVOM to test the exhaust temperature sensor:
If the exhaust temperature sensor is functioning properly, test the reference voltage and ground at the exhaust temperature sensor:
If reference voltage is present:
If reference voltage is not present:
