Powertrain, generic (extended)

P2CF8 Engine Coolant Bypass Valve D Control Circuit Driver Current/Temperature Too High

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

P2CF8 is raised by the driver of coolant bypass valve D when it measures excessive current or overheats and protects itself. No manufacturer documents P2CF8 publicly, and the meaning of D varies: Ford's 2020–2025 gasoline summaries define valve D as the cabin heating valve and report only the smart driver's circuit fault P26BD, plus P26BF from 2024, while GM's 2019 and 2025 tables use the D stuck codes P26C0/P26C2 for the engine block rotary valve. The nearest documented logic is GM's P23C6 for valve C: motor overcurrent with a controller-specific limit of 8.1–12.8 A, 2 s within 5 s, Type B. A seized valve or a shorted motor or coil is the usual trigger. Depending on the loop, heater output or engine warm-up is affected.

Likely causes

Valve stiff or seized, so the motor or solenoid draws excess current

Shorted winding in the valve actuator

Valve wires partly shorted to ground or to each other

Overheated or faulty output stage in the control module

Symptoms

Engine warning lamp
Cabin heat weak or not adjustable (heater valve)
Engine warms up abnormally if the valve sits in the engine loop

Repair estimate

DifficultyMediumWorkshop job

Parts and labour€100–900

Time0.5–3.5 h

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

Parts involved

coolant bypass valve decm

Related codes

P26BD P26BE P26BF P26C1 P23C6

References: fordservicecontent.com, gsi.ext.gm.com, ti.com.