P0598 on Jeep
Thermostat Heater Control Circuit Low
P0598 on Jeep vehicles indicates thermostat heater control circuit low. Au7o has documented this code across 3 Jeep models — most commonly on Commander, Compass, Patriot. This code applies to engines with an electronically controlled (heated) thermostat and means the Powertrain Control Module detected an abnormally low voltage in the thermostat heater control circuit. The heater element lets the computer fine-tune coolant temperature for efficiency and emissions by opening the thermostat sooner under certain conditions. P0598 sets when the control or feedback circuit reads lower than expected (often a short to ground or loss of supply). It is found mainly on certain European makes (BMW, Mercedes, VW/Audi, etc.) and usually has little effect on driving. Typical repair costs on Jeep range from $60 to $1,000, depending on the specific model and root cause.
Common Causes of P0598
- •Faulty electronically controlled (map-controlled) thermostat
- •Short to ground in the heater control wiring
- •Corroded or loose thermostat connector
- •Open or damaged wiring in the control circuit
- •Low coolant level overheating the thermostat heater
- •Blown fuse or poor power supply to the circuit
- •Faulty PCM control driver
P0598 on Jeep by Model
Jeep Commander(1 issue)
- Engine Overheating / Cooling System Failures2006-2010
The Commander is susceptible to engine overheating caused by failing water pumps, cracked radiator tanks, leaking heater core connections, and thermostat failures. The radiator end tanks (plastic) are prone to cracking at the seam where they meet the aluminum core. Power steering cooler line leaks can also compound cooling issues. The 4.7L V8 is especially vulnerable.
Jeep Compass(1 issue)
- Thermostat Housing Coolant Leak2007-2017
The plastic thermostat housing on the 2.0L and 2.4L World engines is prone to cracking and leaking coolant. The housing warps from heat cycling, causing the O-ring seal to fail. This leads to external coolant leaks, overheating, and potential engine damage if not addressed. The same housing is used across Compass, Patriot, and Dodge Caliber platforms.
Jeep Patriot(2 issues)
- Thermostat Housing Coolant Leak / Cracking2007-2017
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.
- Engine Overheating / Water Pump and Radiator Fan Failure2007-2017
Beyond the thermostat housing issue, the Patriot suffers from additional cooling system failures including water pump failure, radiator fan motor burnout, and radiator cap failure. The water pump can develop an internal leak that mixes coolant into the engine oil, causing severe engine damage. The radiator fan may stop working intermittently, leading to overheating in slow traffic or idle.
Looking for P0598 on a different make?
View P0598 across all makes →Frequently Asked Questions
What does P0598 mean on Jeep?▼
P0598 stands for "Thermostat Heater Control Circuit Low." This code applies to engines with an electronically controlled (heated) thermostat and means the Powertrain Control Module detected an abnormally low voltage in the thermostat heater control circuit. The heater element lets the computer fine-tune coolant temperature for efficiency and emissions by opening the thermostat sooner under certain conditions. P0598 sets when the control or feedback circuit reads lower than expected (often a short to ground or loss of supply). It is found mainly on certain European makes (BMW, Mercedes, VW/Audi, etc.) and usually has little effect on driving. On Jeep specifically, this code is documented across 3 models.
What causes P0598 on Jeep vehicles?▼
Common causes on Jeep: Faulty electronically controlled (map-controlled) thermostat, Short to ground in the heater control wiring, Corroded or loose thermostat connector, Open or damaged wiring in the control circuit, Low coolant level overheating the thermostat heater. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0598 on a Jeep?▼
Repair costs on Jeep range from $60 to $1,000, depending on the specific model and root cause.
Which Jeep models have P0598 documented?▼
Au7o has documented P0598 on 3 Jeep models: Commander, Compass, Patriot.