What does it mean?
This generic powertrain diagnostic trouble code (DTC) generally applies to many OBD-II vehicles. This may include, but is not limited to, vehicles from Ford (Mustang, Escape, EcoBoost, etc.), Dodge, Jeep, Land Rover, Nissan, VW, etc.
When a P050E code is stored, it means the Powertrain Control Module (PCM) has detected an exhaust temperature below the minimum threshold during a cold start. A cold start is a term used to describe a driving strategy used only when the engine is at (or below) ambient temperature.
Based on my professional experience, exhaust gas temperature is only monitored in vehicles equipped with clean diesel propulsion systems.
This code is more common in geographical regions with extremely cold climates.
Exhaust temperature changes are essential for reducing emissions in today’s clean diesel engines. The PCM must monitor the exhaust temperature to ensure the desired action is taken to accomplish these drastic temperature changes.
Diesel Exhaust Fluid (DEF) injection systems are responsible for introducing DEF into the catalytic converter and other areas of the exhaust system. These DEF mixtures cause the necessary increase in exhaust temperatures to burn harmful hydrocarbons and trapped nitrogen dioxide particles in the exhaust system. The DEF injection system is controlled by the PCM.
During a cold engine start, the exhaust temperature should be equal to or close to ambient temperature. If the PCM detects that the exhaust temperature is below ambient temperature, a P050E code will be stored and a Malfunction Indicator Lamp (MIL) may illuminate. In most cases, multiple failures will be required for the MIL to illuminate.
Cold Car:
How severe is this DTC?
When a P050E code is stored, DEF injection is likely to be disabled. This code should be classified as severe and rectified urgently.
What are some of the symptoms of the code?
Symptoms of a P050E engine code may include:
Decreased engine performance
Decreased fuel efficiency
Excessive black smoke from the exhaust
Associated DEF codes
What are some common causes of the code?
Causes
of this code may include:
Faulty exhaust temperature sensor
Burned or damaged exhaust temperature sensor wiring
Moisture trapped inside the exhaust has frozen
PCM programming error or faulty PCM
What are the P050E troubleshooting steps?
I would probably start my diagnosis by researching applicable Technical Service Bulletins (TSBs). If I can find one that matches the vehicle I’m working on, the symptoms presented, and the codes that are stored, it is likely to help me diagnose P050E accurately and quickly.
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 to diagnose this code.
The vehicle information source will provide me with diagnostic flowcharts for the P050E, wiring diagrams, connector face views, connector pinout charts, and component testing procedures/specifications. This information will be essential for arriving at an accurate diagnosis.
After a visual inspection of the exhaust temperature sensor wiring and connectors (focusing on wiring routed near high-temperature areas), I would connect the scanner to the vehicle’s diagnostic port and retrieve all stored codes and relevant data. The scanner code data may be useful later in my diagnosis. I would write it down and keep it in a safe place. Now, I would want to clear the codes and test the vehicle (during a cold start) to see if the code resets. The test drive should also displace any moisture that may have been previously trapped in the exhaust system.
Use the DVOM to test the exhaust temperature sensor:
Set the DVOM to the ohms setting
Disconnect the sensor from the wiring harness
Use the manufacturer’s specifications and testing procedures to test the sensor
Discard the sensor if it does not meet the manufacturer’s specifications
If the exhaust temperature sensor is good, test the reference voltage and ground at the exhaust temperature sensor:
With the key on and engine off (KOEO), access the exhaust temperature sensor connector
Set the DVOM to the appropriate voltage setting (reference voltage is typically 5 volts)
Probe the reference pin of the exhaust temperature connector with the DVOM’s positive test lead
Probe the ground pin of the same connector with the DVOM’s negative test lead
The DVOM should read a 5-volt reference (+/- 10%)
If reference voltage is found:
Use the scanner’s data stream display to observe the exhaust temperature
Compare the exhaust temperature displayed on the scanner to the actual temperature you detected using the IR thermometer
If the two differ by more than the maximum allowable threshold, suspect a faulty exhaust temperature sensor
If both are within specifications, suspect a faulty PCM or a PCM programming error
If reference voltage is not found:
With KOEO, connect the DVOM’s negative test lead to a battery ground (with the positive test lead still probing the reference voltage pin of the same connector) to see if you have a voltage problem or a ground problem
A voltage problem will need to be traced back to the PCM
A ground problem will need to be traced back to the appropriate ground junction
The exhaust temperature sensor is often confused with an oxygen sensor
Be cautious when working around a hot exhaust