Turbocharger/Supercharger Boost Control "A" Circuit Range/Performance
P0046 indicates the PCM detected a performance problem with the turbocharger or supercharger boost control solenoid circuit. This code sets when boost pressure control is not operating within the expected range, affecting engine performance and fuel efficiency.
What You Might Notice
- Reduced engine power or acceleration
- Check Engine light illuminated
- Poor fuel economy
- Turbocharger/supercharger not engaging properly
- Black or white smoke from exhaust
Most Common Causes
- 1
Faulty boost control solenoid
The solenoid valve that regulates turbocharger boost pressure may be stuck, clogged, or electrically defective. This is the most common cause of this code.
- 2
Defective boost pressure sensor
The sensor that monitors actual boost pressure may be failing or sending inaccurate readings to the PCM. This prevents proper boost control feedback.
- 3
Wiring or connector issues
Corroded, loose, or damaged wiring and connectors in the boost control circuit can interrupt signal transmission between the PCM and solenoid.
- 4
Vacuum leaks or failed turbocharger
On vacuum-controlled systems, leaks prevent proper solenoid operation. A failing turbocharger itself may also cause boost control problems.
How to Diagnose It
- 1
Check Faulty boost control solenoid — The solenoid valve that regulates turbocharger boost pressure may be stuck, clogged, or electrically defective. This is the most common cause of this code.
- 2
Check Defective boost pressure sensor — The sensor that monitors actual boost pressure may be failing or sending inaccurate readings to the PCM. This prevents proper boost control feedback.
- 3
Check Wiring or connector issues — Corroded, loose, or damaged wiring and connectors in the boost control circuit can interrupt signal transmission between the PCM and solenoid.
- 4
Check Vacuum leaks or failed turbocharger — On vacuum-controlled systems, leaks prevent proper solenoid operation. A failing turbocharger itself may also cause boost control problems.
How to Fix It
- 1
Inspect and test boost control solenoid
Locate the boost control solenoid valve, inspect for debris or damage, test for proper electrical resistance and operation. Replace if faulty or clogged.
- 2
Check and clean solenoid connectors and wiring
Inspect all wiring and connectors related to the boost control circuit for corrosion, looseness, or damage. Clean contacts and repair or replace damaged wiring as needed.
- 3
Test and replace boost pressure sensor
Use a scanner to monitor live boost pressure data. If readings are erratic or inaccurate, the sensor is likely faulty and should be replaced.
- 4
Inspect turbocharger and vacuum system
On vacuum-controlled systems, check for vacuum leaks in hoses and connections. Inspect the turbocharger for internal damage or wear. Replace components as needed.
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