What does code P2040 mean?

Q: What does code P2040 mean?

Reductant Injection Air Pressure Sensor Circuit High Input. P2040 means the engine control module (ECM) has detected a voltage signal from the reductant injection air pressure sensor that is higher than the expected range for the current operating conditions. This sensor monitors the air pressure used to help inject diesel exhaust fluid (DEF) into the exhaust stream, and a high input typically indicates an open circuit, a short to voltage, or a faulty sensor.

DTC codes / P20xx · Fuel and air metering and auxiliary emission controls / P2040

P2040Reductant Injection Air Pressure Sensor Circuit High Input

P2040 means the engine control module (ECM) has detected a voltage signal from the reductant injection air pressure sensor that is higher than the expected range for the current operating conditions. This sensor monitors the air pressure used to help inject diesel exhaust fluid (DEF) into the exhaust stream, and a high input typically indicates an open circuit, a short to voltage, or a faulty sensor.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering and auxiliary emission controls

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.