Turbocharger/Supercharger Boost Control "A" Circuit Low
The PCM detected a low voltage signal from the boost control solenoid circuit, meaning the turbocharger or supercharger boost pressure is not being properly regulated. This prevents the engine from achieving proper boost levels, reducing power and performance.
What You Might Notice
- Reduced engine power and acceleration
- Check engine light illuminated
- Lower than normal boost pressure
- Poor fuel economy
- Engine running in limp mode
Most Common Causes
- 1
Faulty boost pressure/turbocharger position sensor
A malfunctioning sensor sends incorrect voltage signals to the PCM, causing the boost control circuit to read low and trigger the code.
- 2
Defective boost control solenoid
The solenoid valve that regulates boost pressure may be stuck, failed, or producing insufficient electrical signal output.
- 3
Wiring or connector problems
Corroded, damaged, or loose wiring and connectors in the boost control circuit can cause low voltage signals and intermittent faults.
- 4
Vacuum leaks or failed vacuum valve
If the boost control uses vacuum actuation, leaks in vacuum lines or a failed vacuum control valve can prevent proper boost regulation.
How to Diagnose It
- 1
Check Faulty boost pressure/turbocharger position sensor — A malfunctioning sensor sends incorrect voltage signals to the PCM, causing the boost control circuit to read low and trigger the code.
- 2
Check Defective boost control solenoid — The solenoid valve that regulates boost pressure may be stuck, failed, or producing insufficient electrical signal output.
- 3
Check Wiring or connector problems — Corroded, damaged, or loose wiring and connectors in the boost control circuit can cause low voltage signals and intermittent faults.
- 4
Check Vacuum leaks or failed vacuum valve — If the boost control uses vacuum actuation, leaks in vacuum lines or a failed vacuum control valve can prevent proper boost regulation.
How to Fix It
- 1
Inspect and test boost control solenoid
Use a multimeter to check solenoid resistance and voltage output; replace if readings are outside manufacturer specifications or solenoid is stuck.
- 2
Check wiring and connectors
Inspect all wiring and connectors in the boost control circuit for corrosion, damage, or loose connections; repair or replace damaged components and clean corroded contacts.
- 3
Test and replace boost pressure sensor
Verify sensor voltage output under various boost conditions; replace the sensor if it fails to respond correctly to boost pressure changes.
- 4
Inspect vacuum system if applicable
Check vacuum lines for cracks or leaks and inspect vacuum-operated boost control valves; repair leaks or replace damaged vacuum components.
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