Powertrain, generic (extended)

P2DA6 Coolant Heater A Over Temperature

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P2DA6 says coolant heater A, the electric coolant heater of a hybrid or EV, has become too hot. Such heaters measure outlet coolant or housing temperature and switch off above a limit; a Hyundai/Kia patent (US11378000B2) does exactly that, mainly to protect the elements when coolant is missing. Ford is the one maker documented: on 2023 F-150 Lightning trucks built from 31 July 2023 the module SOBDMC can store P2DA6 because of its software. In SSM 52211 the pinpoint test points to software when the ECT2 reading exceeds 70 °C; TSB 23-2375 cures it by reprogramming the SOBDMC and running maximum heat for five minutes. Without symptoms Ford needs no further work; with too little cabin heat, low coolant, air or a pump that does not run are the usual causes.

Likely causes

Software of the controlling module (Ford Lightning SOBDMC), reprogramming
Low coolant level or air trapped in the heater loop
Heater loop coolant pump not running or valve blocking flow
Temperature sensor in heater or loop reading too high

Symptoms

  • Often no noticeable symptom, code found during service
  • Heater switches off, cabin warms only weakly
  • Climate system message, no check engine light

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–800
Time0.5–3 h

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

Parts involved

coolant heater acoolant heater a control module

Related codes

P2DA4P2DA7P2B75U069E

References: static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov, patents.google.com.