P2039

DTC P2039, sometimes indicated as P203900 is an OBD diagnostic trouble code indicating a manufacturer-specific fault with the vehicle powertrain (i.e. engine and gearbox). This code identifies an error with the air/fuel mixture causing reductant injection air pressure sensor "a" circuit low.

This code is related to the air pressure in the reductant injection system. The reductant injection system is used to inject diesel fuel into the exhaust system to reduce emissions. The code is indicating that the air pressure in the system is low. This could be caused by a number of things, including a leak in the system, a clogged filter, or a malfunctioning sensor. If the code is present, the system should be checked for the cause of the problem.

• P2039: Injection Air Pressure Sensor A Circuit Low
• P2039: Reductant Injection Air Pressure Sensor "A" Circuit Low
• P2039: Reductant injection air pressure sensor – low input
• P2039 00: Reductant injection air pressure sensor - low input