The 2021 Ford Transit's diesel engine uses DEF for emissions compliance. System malfunctions trigger warnings and can eventually limit vehicle operation, creating challenges for commercial users.
Transit DEF System
The system monitors DEF quality, level, and injection rate. Commercial Transit use often involves multiple drivers and varying maintenance practices, which can contribute to DEF issues.
Common DEF Problems
Quality Sensor Issues
The quality sensor can fail or become fouled. P20EE indicates the system detects poor DEF quality regardless of actual fluid condition.
Contaminated DEF
DEF contaminated with other fluids triggers warnings. Multiple drivers and fueling locations increase contamination risk.
Crystallization
DEF crystals can form in the system, affecting flow and sensor readings. Crystals develop from air exposure or temperature extremes.
Pump or Injector Failures
The DEF pump and injector can fail, preventing proper fluid delivery to the SCR system.
Commercial Impact
DEF issues can take commercial vehicles out of service. Establishing proper fueling protocols and maintenance schedules minimizes downtime.