Powertrain, generic (extended)

P26D6 Engine Coolant Pump Clutch Control Circuit/Open

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

Some engines drive their mechanical coolant pump through a switchable clutch: following a cold start the pump is left idle so the coolant stays still and the engine reaches temperature sooner, and once a target is met the clutch couples the pump to its drive again. P26D6 means the engine control module sees the control circuit of this clutch as open – typically a broken wire, a loose connector or a solenoid coil that has burnt through. No manufacturer documents this code in public. Ford's OBD summaries list clutched water pumps among the designs its thermostat monitor has to account for, and CARB demands an approved monitoring plan for any part other than the thermostat that regulates coolant temperature. Many clutches engage on loss of current, so the usual effect is slower warm-up rather than overheating.

Likely causes

Broken wire or corroded, loose connector in the clutch control circuit
Open solenoid coil in the coolant pump clutch
Blown fuse or missing supply to the clutch solenoid
Faulty output stage in the engine control module

Symptoms

  • Check engine light on
  • Engine and cabin heater take longer to warm up
  • Coolant temperature behaves differently from normal after a cold start

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–900
Time0.5–3 h

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

Parts involved

coolant pump clutchclutch solenoidwiring harness

Related codes

P26D7P26D8P26D9P26DAP0128

References: law.cornell.edu, fordservicecontent.com, bosch-presse.de.