P0597: Thermostat Heater Control Circuit Open
15 vehicles · 8 makes · $60-$5,000 repair
Most Reported On
P0597 is an OBD-II diagnostic trouble code meaning “Thermostat Heater Control Circuit Open.” P0597 is a cooling-system code indicating an open electrical circuit in the control for the heated (electronically controlled) engine thermostat. Many modern engines use a thermostat with a built-in heater element that the computer can energize to open the thermostat sooner for better temperature management and emissions. When the PCM commands that heater but detects no electrical continuity (an open circuit), it sets this code. It generally means the thermostat heater isn't being controlled, which can affect coolant temperature regulation, fuel economy, and emissions. This code is most commonly reported on 2007-2016 MINI Cooper, 2009-2020 Audi A4, and 2012-2018 Audi A7 (Premium Plus, Prestige), plus 12 other vehicles, with repair costs ranging from $60 to $5,000.
Common Causes
Typical Repair Cost
Based on 16 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
To diagnose P0597, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
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Vehicles Affected (15)
Water Pump/Thermostat Failure
Thermostat Housing Coolant Leak
Coolant Leaks (Thermostat Housing and Hoses)
Coolant / water pump leak on TFSI engines (cracked plastic pump housing)
EA211 Water Pump / Thermostat Housing Coolant Leak
Water Pump and Thermostat Failure (Overheating)
Thermostat Housing Coolant Leak / Cracking
Engine Overheating / Water Pump and Radiator Fan Failure
Thermostat Housing Coolant Leak
Engine Overheating / Cooling System Failures
FAQ
What does P0597 mean?
P0597 stands for "Thermostat Heater Control Circuit Open." P0597 is a cooling-system code indicating an open electrical circuit in the control for the heated (electronically controlled) engine thermostat. Many modern engines use a thermostat with a built-in heater element that the computer can energize to open the thermostat sooner for better temperature management and emissions. When the PCM commands that heater but detects no electrical continuity (an open circuit), it sets this code. It generally means the thermostat heater isn't being controlled, which can affect coolant temperature regulation, fuel economy, and emissions.
What are the most common causes of P0597?
The most common causes of P0597 are: Failed thermostat heater element or integrated control thermostat, Open or broken wiring to the thermostat heater circuit, Corroded, loose, or disconnected thermostat connector, Blown fuse or open in the heater power feed, Poor ground or control-circuit fault from the PCM, Damaged PCM driver for the heater (rare). The specific cause varies by vehicle.
How much does it cost to fix P0597?
Repair costs for P0597 range from $60 to $5,000, depending on the vehicle and root cause.
Which vehicles are affected by P0597?
Au7o has documented P0597 across 15 vehicle models from 8 manufacturers: Audi, BMW, Chevrolet, Dodge, Jeep, MINI, Mercedes-Benz, Skoda.
Sources (12)
- NHTSANHTSA Complaint #11408357 - 2017 Audi A4 coolant pump/water pump failure
- ForumJeepPatriot.com - Thermostat Housing Discussion
- newsMyJeepPatriot.com - Common Problems and Solutions
- partOEM Thermostat Housing Assembly 68003582AB
- NHTSACarComplaints.com - 2006 Commander Engine & Cooling (173 complaints)
- mediaDodge Caliber Overheating - 700R4TransmissionHQ
- mediaDodge Caliber Running Hot - 700R4TransmissionHQ
- ForumOverheating issue needing help - Dodge Caliber Forums
- ForumWheres the radiator fluid going - Dodge Caliber Forum
- ForumMy Audi Q2 (2018) water pump is leaking coolant at only 30,000 miles — JustAnswer UK
- Forum1.4 TFSI Audi Q2 coolant loss — Honest John Back Room Forum
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.