180001

What the code means

180001 belongs to the cooling category and carries major severity. The code sets when there's a fault in the engine cooling circuit. According to the source, the likely culprits are the coolant temperature sensor or the thermostat.

Normally the DME continuously monitors coolant temperature through the sensor and controls the thermostat, holding operating temperature within a narrow range. If the sensor sends an incorrect signal or the thermostat stops switching between circuits, the control unit sees a temperature that doesn't match what's expected and sets the fault.

Symptoms

• Engine overheating;
• weak heater output — the heater blows cold air or barely warm air;
• the check engine light comes on.

Diagnosis and repair

1. Check the coolant level. A low level on its own causes overheating and weak cabin heat.
2. Check the thermostat — if it's stuck open, the engine won't reach operating temperature; if it's stuck closed, it overheats.
3. Check the coolant temperature sensor: incorrect readings mislead the DME and can cause either a false overheat warning or an actual overheat.
4. Replace the faulty components.

Secondary issues

The source includes a warning about possible secondary consequences not directly related to the cooling system: impacts the car has taken may damage the suspension, suspension components can work loose or weaken, and rattles and squeaks can appear in the interior. The source doesn't confirm a link between these items and code 180001 — when diagnosing, rely first on the cooling system data.