GreenDieselEngineering wrote:
This error code is for the airbox pressure sensor, which is located on the air box lid toward the driver's side, just below the mass air flow sensor. The code is signaling that the sensor is not making connection or failed internally. The connector for this sensor tends to come loose at times because the retention clip sometimes breaks. Hopefully this will fix your issue. If it is making good connection, the sensor reading is most likely drifting and would need replacement.
My CRD was in Limp Mode. My code reader reported code
p1854 as well. For some reason, many sites list this as a transmission code? I can confirm that on the CRD it is the pressure sensor. My connector was clean and good so I swapped mine out with a spare and cleared the code. Started it up with no issues, the engine was back to full power and the code was gone! Thanks for this response GDE!
Air Box Pressure Sensor