Civic Diesel Exhaust Pressure Issue

I also drive a Civic diesel and had similar symptoms, including the warning light and reduced power. If the diagnostic says the pressure is low, it's quite possible that the exhaust back pressure sensor is faulty. This sensor measures the pressure in the exhaust system, which is needed for proper DPF regeneration. DPF regeneration is a process where the accumulated soot in the particulate filter is burned off. If the sensor is defective, the engine control unit (ECU) receives incorrect data and can't initiate or control the DPF regeneration, and thus the car will show these symptoms. Have you checked the sensor for any visible damage or loose connections?

I'm not experienced with automotive repairs, so I haven't inspected the sensor. Could you elaborate on the location of the exhaust back pressure sensor, and would a visual inspection be enough to confirm it's failing?

Without proper tools and expertise, a visual inspection won't tell you much beyond obvious physical damage. The sensor is usually located near the diesel particulate filter (DPF) in the exhaust system, but its exact position can vary. Since you're experiencing multiple symptoms, and the diagnostic points to a sensor issue, I'd recommend taking it to a trusted workshop. They can properly diagnose the sensor and replace it if necessary. Continuing to drive with a faulty DPF system can cause further damage.

I will schedule an appointment with my local mechanic to have the exhaust back pressure sensor inspected and replaced. The estimated repair cost is 245€. Thanks for the help.