Powertrain, generic (extended)

P2B59 Engine Coolant Flow Control Valve Control Circuit/Open

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P2B59 is the open-circuit check for the drive of the coolant flow control valve. In GM's 25OBDG04B (3.0 L Duramax) the driver reports a load resistance above 200 kΩ, meaning one of the motor wires is disconnected; 80 of 100 samples set a Type B fault. Hyundai and Kia also use the code on the 2.5-litre Theta III engines with an integrated thermal management module (ITM): bulletins 26-EM-009H (Sonata, Tucson) and Kia TSB ENG 264 (K5, Sorento, Sportage, 2024–2025) describe P2B59F0 caused by an ECU logic error and fix it with new software, noting no driveability effect. Otherwise check the connector, the harness and the valve motor. Shorts to ground and to supply are reported separately as P2B5A and P2B5B.

Likely causes

ECU judgement logic on Hyundai/Kia 2.5 Theta III (software update 26-EM-009H / ENG 264)
Valve connector unplugged, loose or with a pushed-out terminal
Motor wire broken in the harness or valve motor winding open

Symptoms

  • MIL on, often without any noticeable driveability change
  • Valve stays in its default position, slower warm-up possible

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–1,200
Time0.3–4 h

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

Parts involved

engine coolant flow control valvewiring harnessecm

Related codes

P2B5AP2B5BP2B58P2B5C

References: gsi.ext.gm.com, static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov.