P220E: Upstream NOx heater performance has electrical and control branches

P220E is the upstream NOx sensor heater control range/performance code in Ford’s diesel summary. It covers several heater-monitor observations, so the word performance does not restrict the diagnosis to slow heating alone.

Four listed ways the heater can fail its checks

Ford identifies hardware-detected open circuit, short to battery, short to ground, and a rationality check in which heater duty cycle differs from expectation by more than 20%. The listed electrical examples include heater voltage above 5 V for the short-to-battery branch and zero voltage for the short-to-ground branch.

Those values belong to the documented internal monitoring strategy. They are not a connector pinout or permission to apply voltage externally. The duty-cycle branch also needs its expected value; a duty reading without the matching expectation cannot reproduce the comparison.

Use failure detail to choose the next diagnostic question

A continuity-type result and a control-effort discrepancy call for different evidence. Preserve the reporting sensor identity and accompanying NOx supply or communication codes before concluding that the heater element itself is defective.

Ford lists this code for bank-one sensor one, while P220F addresses the tailpipe sensor’s heater checks elsewhere in the document. The two should not be interchanged solely because both are NOx heaters. The summary does not provide a complete thermal test procedure or a replacement instruction. Its useful contribution is to distinguish the electrical and rationality routes hidden behind one broad heater-performance label.

Source and applicability

This explanation follows Ford’s 2023–2024 diesel OBD summary. Match the vehicle’s engine and calibration before applying these monitor values; a generic code alone does not establish fitment. Ford PDF, page 23 · Ford PDF, page 24.