What are the common causes of P004A?

An open in the boost control B circuit. A failed boost control B solenoid. Corrosion at the boost control B connector. Chafed wiring along the boost control B harness. A failed ECM driver for boost control B.

Inspect the boost control B connector and wiring for an open. Measure the boost control B solenoid resistance. Check the control circuit for voltage with the key on. Command the boost control B solenoid and listen for it to cycle. Replace the boost control B solenoid if it does not respond. Clear the code and retest.

P004A

Turbocharger/Supercharger Boost Control B Circuit/Open

System: Fuel and air metering (P code)
Lamp: Check Engine Light
Category: Powertrain - Fuel/Air Metering

What it means

P004A means Turbocharger/Supercharger Boost Control B Circuit/Open.

Check these first

An open in the boost control B circuit
A failed boost control B solenoid
Corrosion at the boost control B connector
Chafed wiring along the boost control B harness
A failed ECM driver for boost control B

What to do next

Inspect the boost control B connector and wiring for an open
Measure the boost control B solenoid resistance
Check the control circuit for voltage with the key on
Command the boost control B solenoid and listen for it to cycle
Replace the boost control B solenoid if it does not respond
Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.