P2B59Engine Coolant Flow Control Valve Control Circuit/Open
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- 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.
- What you may notice
- MIL on, often without any noticeable driveability change
- Valve stays in its default position, slower warm-up possible
- Likely causes
- LikelyECU judgement logic on Hyundai/Kia 2.5 Theta III (software update 26-EM-009H / ENG 264)
- PossibleValve connector unplugged, loose or with a pushed-out terminal
- PossibleMotor wire broken in the harness or valve motor winding open
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €0 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.