Powertrain, generic (extended)

P24F3 Reductant Tank Temperature/Fuel Temperature Correlation

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P24F3 sets the temperature reported from the DEF (reductant) tank against the fuel temperature. After a long soak both liquids rest close to ambient, so a clear mismatch exposes a sensor that reads wrong although each signal may be electrically valid. No manufacturer explains P24F3 in a public service document. Ford's 2023 diesel summary shows the same principle with other partners: P205B flags more than 40 °C between tank and DEF quality sensor temperature at start-up, and P0181 holds fuel temperature against the charge-air reading after six hours off. CARB requires such rationality checks for input sensors that feed emission controls. Where the DEF sensor is built into the tank module, the fix can mean a costly tank unit; driving is normally unaffected.

Likely causes

DEF tank temperature sensor (often integrated in the tank or sender module) reading wrong
Fuel temperature sensor drifting
Local heat source such as an exhaust leak warming one sensor
Contact resistance in a sensor connector

Symptoms

  • Warning lamp, often after a cold start
  • DEF tank and fuel temperature far apart in live data after an overnight stop

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€120–1,200
Time0.5–3 h

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

Parts involved

reductant tank temperature sensorfuel temperature sensor

Related codes

P205BP205AP0181P0182P0183

References: fordservicecontent.com, law.cornell.edu.