Powertrain, generic (extended)

P2B66 Coolant Pump D Control Circuit/Open

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2B66 is the open-circuit code for the control line of coolant pump D, the pump a manufacturer labels D in its thermal management. The driver stage in the engine computer detects a broken wire, an unplugged connector or a pump input that no longer draws current. No manufacturer documents this exact code publicly. Ford's 2024 summary shows the analogous logic for pumps A and B (P2600, P261A): a continuous check from 11 V battery voltage, in which the smart driver reports the output fault. Under CARB 13 CCR 1968.2 (e)(15), output components must be watched for circuit faults. A short to ground is P2B67, a short to voltage P2B68; pumps C and E use P26F4 and P2DF4. Without control the pump stays off and its loop loses cooling.

Likely causes

Pump connector loose, corroded or unplugged
Control wire broken between engine computer and pump
Control input inside the pump open

Symptoms

  • Warning lamp with stored code
  • Pump D does not respond to commands
  • Higher temperature in the loop served by pump D

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–700
Time0.5–3 h

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

Parts involved

coolant pump dwiring harnessecm

Related codes

P2B67P2B68P2B69P26F4P2DF4

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