P0597: How to Diagnose & Fix — Thermostat Heater Control Circuit Open
19 vehicles · 11 makes · $60-$5,000 repair
How to diagnose and fix P0597: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
MINI Cooper · 2007–2016
Both R56 and early F56 Coopers use an electric thermostat housing and electric water pump that are prone to premature failure. The thermostat housing cracks causing coolant leaks, and the water pump impeller can fail leading to overheating.
Common Symptoms
- Coolant warning light
- Overheating
- Coolant puddle under car
- Heater blowing cold air
- Temperature gauge fluctuation
How to Fix
Replace thermostat housing assembly and/or electric water pump. Use updated MINI parts. The thermostat housing is on the front of the engine and relatively accessible. Water pump is belt-driven on N12/N16, electric on newer B38/B48.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Saleri MINI water pump 11517648827OEMSaleri PA1425 / MINI 11517648827
Confirm VIN, engine and current interchange before purchase; this is not an el
- Mahle MINI thermostat assembly 11538699290OEMMahle TM57105 / MINI 11538699290
R56 N12/N14 and VIN-confirmed N16 thermostat-housing branch Fitment/availability: The inspected direct U.S. Confirm VIN, engine, production date and connector; do not use for an N18 or
- Rein MINI thermostat housing 11538674895OEMRein CTA0051 / MINI 11538674895
R56 N18 and VIN-confirmed later N16 thermostat-housing branch Fitment/availability: The inspected direct U.S. Use only after VIN, engine and connector verification confirms the N18-style branch; do not infer it from
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Audi A7 · 2012–2018
The 3.0T V6 thermostat housing in the C7 A7 develops coolant leaks from the plastic housing and its O-ring seals. The housing is located at the front of the engine and cracks or warps over thermal cycling. Coolant leaks onto the serpentine belt area and can cause belt slippage or overheating if coolant loss is significant.
Common Symptoms
- Coolant puddle under front of vehicle
- Sweet coolant smell from engine bay
- Low coolant warning light
- Coolant visible on serpentine belt
- Temperature gauge reading higher than normal
- Steam from engine bay
- Coolant residue around thermostat housing area
How to Fix
Replace the thermostat housing assembly with an updated part. The O-ring seals should always be replaced. Some owners upgrade to aluminum aftermarket housings for improved durability. The water pump should be inspected during this repair as it shares the same coolant circuit.
Sources for this issue (1)
Jeep Patriot · 2007–2017
The plastic thermostat housing on the 2.0L and 2.4L World engines cracks from heat cycling, causing coolant leaks and potential engine overheating. This is the same design flaw shared with the Jeep Compass and Dodge Caliber that use the same engine family. The plastic becomes brittle over time and cracks at the O-ring seal area.
Common Symptoms
- Coolant leak near thermostat on engine
- Low coolant warning light
- Engine overheating
- Sweet coolant smell under hood
- White crusty residue around thermostat area
- Temperature gauge runs hot
How to Fix
Replace the plastic thermostat housing with the upgraded aluminum version. OEM part number 68003582AB or aftermarket Dorman 902-319 ($30-60). The aluminum housing eliminates the cracking problem permanently. The assembly includes the housing, thermostat, temperature sensor, and O-ring. Parts cost $30-80, labor 1-2 hours. Very DIY-friendly repair with basic tools.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Dorman 902-319 engine-coolant thermostat housing assemblyOEMDorman 902-319
Plastic housing/thermostat/O-ring assembly replacement when the matching five-port housing is confirmed leaking or damaged Fitment/availability: 2007-2017 Patriot 2.0L/2.4L; 2007-2008 requires the later 2009-and-newer heater-hose design,…
- Genuine Mopar 68676479AA upper thermostat-housing coverOEMMopar 68676479AA
OEM upper-cover replacement when the pressure-tested leak is isolated to that catalog branch Fitment/availability: Current upper-cover supersession for 4884571AB on specified Patriot 2.0L/2.4L applications; confirm VIN because catalog ye…
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Owner tips & cautions
- TipThis is an easy DIY repair - drain some coolant, remove 2 bolts, swap housing, refill and bleed air from system
Sources for this issue (1)
Jeep Patriot · 2007–2017
Chevrolet Camaro · 2016–2023
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P0597 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
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 19 vehicle models from 11 manufacturers: Audi, BMW, Buick, Cadillac, Chevrolet, Dodge, Jeep, MINI, Mercedes-Benz, Skoda, Volkswagen.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.