P0599 on MINI
Thermostat Heater Control Circuit High
P0599 on MINI vehicles indicates thermostat heater control circuit high. Au7o has documented this code across 2 MINI models — most commonly on Cooper, GP. This code relates to the engine cooling system's thermostat heater control circuit, used on engines with an electrically heated (map-controlled) thermostat that the computer can open early to fine-tune coolant temperature. The 'high' designation means the computer detected the control circuit voltage was higher than expected, indicating an electrical fault such as a short to voltage or an open circuit. It is generally an electrical/wiring problem rather than a mechanical cooling failure. It can affect how precisely the engine manages its operating temperature and fuel economy. Typical repair costs on MINI range from $400 to $1,200, depending on the specific model and root cause.
Common Causes of P0599
- •Faulty electronically heated thermostat element/heater
- •Short to voltage in the heater control circuit
- •Open or damaged wiring/connector
- •Corroded or loose connector at the thermostat
- •Poor electrical ground
- •Faulty PCM/ECM driver (less common)
P0599 on MINI by Model
MINI Cooper(1 issue)
- Electric Thermostat and Water Pump Failure2007-2016
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.
MINI GP(1 issue)
- Electric Water Pump Failure2013-2023
The electric water pump on the N18 and B48 engines is a known failure point across the BMW/MINI platform. The pump motor or impeller fails, causing loss of coolant circulation and rapid overheating. Unlike mechanical water pumps that give gradual warning signs, the electric pump can fail suddenly with no prior symptoms. The GP engines run hotter than standard MINI models, putting additional stress on the pump. Failure typically occurs between 50,000-100,000 miles.
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View P0599 across all makes →Frequently Asked Questions
What does P0599 mean on MINI?▼
P0599 stands for "Thermostat Heater Control Circuit High." This code relates to the engine cooling system's thermostat heater control circuit, used on engines with an electrically heated (map-controlled) thermostat that the computer can open early to fine-tune coolant temperature. The 'high' designation means the computer detected the control circuit voltage was higher than expected, indicating an electrical fault such as a short to voltage or an open circuit. It is generally an electrical/wiring problem rather than a mechanical cooling failure. It can affect how precisely the engine manages its operating temperature and fuel economy. On MINI specifically, this code is documented across 2 models.
What causes P0599 on MINI vehicles?▼
Common causes on MINI: Faulty electronically heated thermostat element/heater, Short to voltage in the heater control circuit, Open or damaged wiring/connector, Corroded or loose connector at the thermostat, Poor electrical ground. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0599 on a MINI?▼
Repair costs on MINI range from $400 to $1,200, depending on the specific model and root cause.
Which MINI models have P0599 documented?▼
Au7o has documented P0599 on 2 MINI models: Cooper, GP.