Hours: 07–23 daily

TuningBot DTC Database · v4.37.15

P0478 Exhaust Pressure Control Valve High

Generic (OBD-II) interpretation in the TuningBot DTC database.

P · PowertrainEmissionsOBD2

What P0478 means

P0478
Exhaust Pressure Control Valve High Generic · emissions Data confidence 90%

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.

Possible causes

  • Wiring short to positive
  • exhaust gas pressure control valve
  • ECM

Related and nearby codes

How to read P0478

P

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.

Other file services

ECU tuningDyno-tested results by model and engine See the results →

← Search the full DTC database