The control module registered the fault condition described as "Heated Catalyst Internal Control Module Checksum/ROM Error". This is the manufacturer-specific definition used by BMW.
TuningBot DTC Database · v4.37.15
P1303 BMW - Heated Catalyst Internal Control Module Checksum/ROM Error
Manufacturer-specific interpretation for BMW. All interpretations of P1303
What P1303 means
Related and nearby codes
How to read P1303
Powertrain: engine, transmission and driveline systems.
Manufacturer-defined range: the meaning can differ between brands.
Specific fault index within the subsystem.
Frequently asked questions about P1303
What does P1303 mean?
Heated Catalyst Internal Control Module Checksum/ROM Error. The control module registered the fault condition described as "Heated Catalyst Internal Control Module Checksum/ROM Error". This is the manufacturer-specific definition used by BMW.
Is P1303 generic or manufacturer-specific?
P1303 is a manufacturer-specific code. In this database it is documented for: BMW. The same number can mean something different on other brands.
Can TuningBot remove P1303 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.
Other file services
Understand the system behind this code: Checksum in ECU Files
