Generic (OBD-II) interpretation in the TuningBot DTC database.
P · PowertrainEmissionsOBD2
What P0478 means
P0478
Exhaust Pressure Control Valve High
Generic · emissions
Data confidence90%
The control module detected a fault associated with the Exhaust Pressure Control Valve High circuit or function; the stored code identifies the affected component rather than a single failure mode.
Powertrain: engine, transmission and driveline systems.
0
Generic SAE-standard code: same meaning on every make.
478
Specific fault index within the subsystem.
Frequently asked questions about P0478
What does P0478 mean?
Exhaust Pressure Control Valve High. The control module detected a fault associated with the Exhaust Pressure Control Valve High circuit or function; the stored code identifies the affected component rather than a single failure mode.
Is P0478 generic or manufacturer-specific?
P0478 is a generic OBD-II code: it has the same meaning on every make and model that follows the SAE standard.
Can TuningBot remove P0478 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.