P0597 fault code: what it means

P0597: Electric thermostat heater circuit open. BMW map-controlled thermostats fail electrically; engine may run cold or hot.

Engine and gearbox (powertrain) · Minor

Usual causes, most likely first

map-controlled thermostat heater failed
thermostat connector or wiring

P0597 by make

BMW

Electric thermostat heater circuit open. BMW map-controlled thermostats fail electrically; engine may run cold or hot.

Usual causes: map-controlled thermostat heater failed; thermostat connector or wiring

Volvo

Thermostat heater control circuit open. Many later Volvo petrol engines use an electronically controlled thermostat; cooling fans may run all the time.

Usual causes: failed thermostat heater element; wiring or connector at thermostat

Not sure what P0597 means on your car? Ask Credov.

Before you clear it

Write the code down or photograph the scanner first. A code that comes straight back after clearing points to a fault that is still there. A car whose codes were cleared just before you arrived may be hiding one: the scanner's readiness monitors show "not ready" for a while after codes are cleared.

Researched by Credov from manufacturer and workshop sources. A fault code points to where a fault may be; a workshop confirms it with a diagnosis. Browse all fault codes.