P050E Too low engine exhaust gas temperature during cold start

P050E Too low engine exhaust gas temperature during cold start

OBD-II DTC Datasheet

Engine exhaust gas temperature too low during cold start

What does this mean?

This Generic Powertrain Diagnostic Trouble Code (DTC) is commonly applied to many OBD-II vehicles. This may include, but is not limited to, Ford vehicles (Mustang, Escape, EcoBoost, etc.), Dodge, Jeep, Land Rover, Nissan, VW, etc.

When a code P050E is stored, it means that the powertrain control module (PCM) has detected an exhaust gas temperature below the minimum cold start threshold. Cold start is a term used to describe a driving strategy used only when the engine is at (or below) ambient temperature.

In my professional experience, exhaust gas temperature is only monitored in vehicles equipped with clean diesel power plants.

This code is more common in geographic regions with very cold climates.

Exhaust gas temperature changes are critical to reduce emissions in modern clean combustion diesel engines. The PCM must monitor the temperature of the exhaust gases to ensure that the desired action is being taken to achieve these sudden temperature changes.

Diesel Exhaust Fluid (DEF) injection systems are responsible for injecting DEF into the catalytic converter and other areas of the exhaust system. These DEF blends cause an elevated exhaust gas temperature to burn off harmful hydrocarbons and nitrogen dioxide particles trapped in the exhaust system. The DEF injection system is controlled by the PCM.

During a cold start, the exhaust gas temperature should be at or near ambient temperature. If the PCM detects that the exhaust gas temperature is lower than the ambient temperature, a code P050E will be stored and a malfunction indicator lamp (MIL) may illuminate. In most cases, it will take several failures to illuminate the MIL.

Cold machine:

What is the severity of this DTC?

When the P050E code is stored, DEF injection is likely to be disabled. This code should be categorized as serious and urgently corrected.

What are some of the symptoms of the code?

Symptoms of a P050E engine code may include:

• Reduced engine performance
• Reduced fuel efficiency
• Excessive black smoke from the exhaust pipe
• Accompanying DEF Codes

What are some of the common causes for the code?

Reasons for this code may include:

• Defective exhaust gas temperature sensor
• Burnt or damaged exhaust gas temperature sensor wiring
• Moisture inside the exhaust pipe is frozen
• PCM or PCM programming error

What are some of the P050E troubleshooting steps?

I would probably start my diagnosis by looking for the relevant Technical Service Bulletins (TSB). If I can find one that matches the vehicle I am working with, the symptoms shown and the codes stored, it will most likely help me diagnose P055E accurately and quickly.

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 block diagrams for the P055E, wiring diagrams, connector types, connector pinout diagrams, and component test procedures / specifications. This information will aid in making an accurate diagnosis.

After visually inspecting the exhaust gas temperature sensor wiring and connectors (paying particular attention to the wiring near the high temperature zones), I connected the scanner to the vehicle's diagnostic port and retrieved all stored codes and related data. The code data from the scanner can be useful in the future when making a diagnosis. I would write it down and keep it in a safe place. Now I would clear the codes and test drive the car (on cold start) to see if the code is cleared. During the test drive, moisture that may have previously remained in the exhaust system should also be displaced.

Use DVOM to check the exhaust gas temperature sensor:

• Set DVOM to Ohm setting
• Disconnect the sensor from the wire harness.
• Use manufacturer's specifications and test procedures to verify the sensor.
• Dispose of the sensor if it does not meet the manufacturer's specifications.

If the exhaust gas temperature sensor is OK, check the reference voltage and ground at the exhaust gas temperature sensor:

• With the key on and the engine off (KOEO), access the exhaust gas temperature sensor connector.
• Set the DVOM to the appropriate voltage setting (the reference voltage is typically 5 volts).
• Check the test pin of the exhaust temperature connector with the positive test lead from the DVOM.
• Check the grounding pin of the same connector with the negative test lead of the DVOM.
• The DVOM should indicate a 5 volt reference voltage (+/- 10 percent).

If a reference voltage is detected:

• Use the scanner's data flow display to monitor the exhaust gas temperature.
• Compare the exhaust gas temperature displayed on the scanner with the actual temperature that you determined with an IR thermometer.
• If they differ by more than the maximum permissible threshold, suspect a malfunction of the exhaust gas temperature sensor.
• If they are within specifications, suspect a defective PCM or programming error.

If no voltage reference is found:

• Using KOEO, connect the negative test lead of the DVOM to battery ground (with the positive test lead still examining the reference voltage pin of the same connector) to see if you have a voltage problem or a ground problem.
• The voltage problem must be traced back to the PCM.
• The ground problem will need to be traced back to an appropriate ground connection.

• An exhaust gas temperature sensor is often confused with an oxygen sensor.
• Use caution when working with hot exhaust

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