Powertrain, generic (extended)

P205D Reductant Tank Temperature Sensor A Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P205D is the top-of-range fault of the tank's temperature sensor. On voltage-read NTC sensors a high signal looks like extreme cold and typically comes from an open circuit, a lost ground or a short to supply: Ford's 2023 diesels set it above 4.3 V, GM's 2025 DEF controller above 4.75 V (about −40 °C, 0.5 s, Type A), and GM's 2018 diesel table above 60,000 Ω. On the 6.6L LML and 2014 Cruze GM reads a CAN raw value instead, where High means above 1022, i.e. 160 °C or more, the hot side (6 s, Type B). Ford's bulletin 18-2190 for 2011–2015 6.7L Super Duty treats P205D like P205C: new reductant heater and sender assembly plus PCM update. Hino names P205D next to P205B and P205C as a source of wrong DEF temperature input. The low end is P205C.

Likely causes

Open circuit, unplugged connector or broken ground
Sensor in the heater/sender assembly open internally
Signal wire shorted to supply voltage

Symptoms

  • MIL and DEF warning
  • Tank heater runs although the tank is warm
  • Dosing delayed after start

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€60–1,200
Time0.5–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

reductant tank temperature sensor

Related codes

P205AP205CP205BP2043P2ADC

References: gsi.ext.gm.com, fordservicecontent.com, static.nhtsa.gov, static.nhtsa.gov.