Turbocharger/Supercharger Boost Control "A" Circuit/Open
The PCM detected an open circuit in the boost control solenoid circuit, preventing proper turbocharger or supercharger boost pressure regulation. This code applies to vehicles with variable boost control systems and indicates the solenoid valve cannot receive proper electrical commands.
What You Might Notice
- Reduced engine power and acceleration
- Poor fuel economy
- Engine running in limp mode
- Turbocharger not spooling properly
- Check engine light illuminated
Most Common Causes
- 1
Open or broken wiring in solenoid circuit
Damaged, corroded, or disconnected wiring harness between PCM and boost control solenoid valve. Check for breaks, loose connectors, or corrosion at connection points.
- 2
Faulty boost control solenoid valve
The solenoid coil has failed or is stuck, preventing it from opening and closing to regulate boost pressure. The solenoid may be internally shorted or have a burnt coil.
- 3
Defective turbocharger boost pressure sensor
The pressure sensor reading is incorrect or the sensor circuit is open, causing the PCM to detect a circuit fault. A faulty sensor cannot provide proper feedback for boost control.
- 4
Faulty PCM or control module
The powertrain control module has internal faults preventing it from properly operating the boost control circuit. This is less common but possible if wiring and solenoid test good.
How to Diagnose It
- 1
Check Open or broken wiring in solenoid circuit — Damaged, corroded, or disconnected wiring harness between PCM and boost control solenoid valve. Check for breaks, loose connectors, or corrosion at connection points.
- 2
Check Faulty boost control solenoid valve — The solenoid coil has failed or is stuck, preventing it from opening and closing to regulate boost pressure. The solenoid may be internally shorted or have a burnt coil.
- 3
Check Defective turbocharger boost pressure sensor — The pressure sensor reading is incorrect or the sensor circuit is open, causing the PCM to detect a circuit fault. A faulty sensor cannot provide proper feedback for boost control.
- 4
Check Faulty PCM or control module — The powertrain control module has internal faults preventing it from properly operating the boost control circuit. This is less common but possible if wiring and solenoid test good.
How to Fix It
- 1
Inspect and repair wiring harness
Visually inspect the boost control solenoid wiring for damage, corrosion, or loose connectors. Repair or replace damaged wiring and ensure all connectors are clean and fully seated.
- 2
Test solenoid with multimeter
Use a multimeter to check continuity and resistance of the solenoid coil. Compare readings to manufacturer specs. Replace the solenoid if resistance is infinite or incorrect.
- 3
Check boost pressure sensor
Test the turbocharger boost pressure sensor for proper voltage output and signal integrity. Replace if sensor readings are out of range or signal is absent.
- 4
Inspect for vacuum leaks if applicable
For vacuum-controlled boost solenoids, check vacuum lines for cracks or disconnections. Repair or replace damaged vacuum lines and verify proper vacuum supply to the valve.
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