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P004B fault code: what it means

P004B: Turbo boost control B circuit range/performance: on twin-turbo 3.0 SDV6 the second turbo's actuator is not reaching its commanded position.

Engine and gearbox (powertrain) · Costly if missed

Usual causes, most likely first

  1. sticking or failed turbo actuator on bank B / secondary turbo
  2. sooted or seized turbo vanes
  3. actuator wiring

P004B by make

Land Rover

Turbo boost control B circuit range/performance: on twin-turbo 3.0 SDV6 the second turbo's actuator is not reaching its commanded position.

Usual causes: sticking or failed turbo actuator on bank B / secondary turbo; sooted or seized turbo vanes; actuator wiring

Not sure what P004B 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.