P20F5 OBD-II: Reductant Consumption Too High

OBD II Fault Code

• OBD II P20F5

OBD-II Code NOx sensor failure is defined as a Reductant Consumption Too High

Diesel Exhaust Fluid (DEF) is used to assist in converting leftover exhaust particles to harmless gases. In order to burn off those particles, the temperature of the exhaust system needs to increase. the injection of DEF Fluid into the exhaust stream brings Diesel Particulate Filter (DPF) up to temperature. The system is then able to convert harmful NOx to Nitrogen, Carbon Dioxide, and water. The Reductant Catalyst (SRC) was added to further reduce any NOx was still in the exhaust stream. If the system uses too much DEF, code P20F5 will be stored.

NOx sensor failure Symptoms

• DPF regeneration may not occur

Common Problems That Trigger the P20F5 Code

• DEF contamination
• DEF injector failure
• NOx sensor failure