Engine coolant temperature (ECT) sensor - open circuit/short to positive
VAG · thermal_management
Data confidence62%
The control module detected an interruption (open circuit) in the Engine coolant temperature (ECT) circuit, so the expected electrical continuity was not present. This is the manufacturer-specific definition used by Audi.
Possible causes
Wiring open circuit/short to positive
ECT sensor
Applies toAudi
P1256
Engine Coolant Temperature Circuit (G62): Open / Short to B+
VAG · thermal_management
Data confidence88%
The control module detected a short circuit to battery voltage in the Engine Coolant Temperature Circuit (G62): Open / circuit. This is the manufacturer-specific definition used by Volkswagen. Volkswagen Group tools also report it as fault code 17664. Documented across Volkswagen Group applications (Audi, SEAT and Škoda included).
Symptoms
Difficulties with starting a cold engine
RPM at idle is irregular
With all engine temperatures seldom idle rpm will vary between 900 - 1000 rpm
Bad acceleration during warming up
Possible causes
Wiring and/or connections faulty
Engine Coolant Temperature Sensor (G62) faulty
Recommended checks
Check wiring and connections
Check / Replace Engine Coolant Temperature Sensor (G62)
Powertrain: engine, transmission and driveline systems.
1
Manufacturer-defined range: the meaning can differ between brands.
256
Specific fault index within the subsystem.
Frequently asked questions about P1256
What does P1256 mean?
Diagnostic Trouble Code (2 interpretations). The control module detected an interruption (open circuit) in the Engine coolant temperature (ECT) circuit, so the expected electrical continuity was not present. This is the manufacturer-specific definition used by Audi.
Is P1256 generic or manufacturer-specific?
P1256 is a manufacturer-specific code. In this database it is documented for: VAG. The same number can mean something different on other brands.
Can TuningBot remove P1256 at file level?
If the fault logic lives in the ECU calibration, yes: our DTC Removal file service disables the specific fault entry. Checksum correction is not included: it is a separate, optional service. Not sure whether your case qualifies? Request a free assessment and our engineers will check your ECU file.