Powertrain, generic (extended)

P24FF Reductant Temperature Too High

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P24FF signals that the diesel exhaust fluid itself has become too hot while the engine runs. The controller reads the DEF temperature sensor in the tank and flags a value above its limit during operation; hot urea solution ages faster and can form deposits. Deutz lists P24FF-00 in its EMR L1 secondary ECU code table (SPN 4337, FMI 11) as AdBlue overtemperature in operation, kept apart from its own warning and critical overtemperature codes. Volvo truck solution KC-10 names a typical hardware cause: when guided diagnostics finds the valve working yet the DEF is confirmed hot, the coolant solenoid valve that heats the tank may be fitted against its flow arrow; turning the valve body around fixes it. Sensor circuit faults are P205A to P205D.

Likely causes

DEF tank coolant solenoid valve installed against its flow direction (Volvo)
Tank heating valve stuck open so hot coolant keeps flowing
Missing heat shield or exhaust leak warming the tank or lines
DEF temperature sensor reading too high

Symptoms

  • Warning lamp with SCR or DEF message
  • DEF tank temperature far above ambient in live data

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€100–900
Time0.5–3 h

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

Parts involved

reductant tankreductant tank heaterreductant tank temperature sensor

Related codes

P205AP205BP205CP205DP20B9

References: static.nhtsa.gov, serdia.deutz.com.