P0033
Turbocharger/Supercharger Bypass Valve A Control Circuit
Turbo / boost control
Generic OBD-II
High
What it means
P0033 means the ECM detected a fault in the control circuit for the turbo/supercharger bypass (diverter) valve "A". That valve vents excess boost, so a circuit fault leaves boost control unreliable — you may feel reduced or surging power. The usual causes are the control solenoid, its connector, or wiring. Despite some databases flagging this as a misfire code, it is a boost-control circuit fault.
High
Can I keep driving? Yes — you may notice reduced boost and power; drive gently until repaired to avoid over-working the turbo system.
Common symptoms
What you'll notice
- Check-engine light on
- Reduced power or acceleration
- Boost that surges or falls off
- Possible turbo flutter or unusual intake noise
Common causes
Most likely first
- Failed bypass (diverter) valve control solenoidLikely
- Open or short in the bypass valve control circuitCommon
- Loose or corroded connector at the solenoidCommon
- ECM control-circuit driver faultLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data to confirm when the fault sets.
- Inspect the bypass valve solenoid connector and wiring for opens, shorts, or corrosion.
- Measure the solenoid resistance and command it with a scan tool to confirm it actuates.
- Check for correct power and ground at the solenoid connector.
- Replace the solenoid if faulty; consider the ECM only after wiring checks out.
FAQ
Quick answers
Is it safe to drive with P0033?+
Short trips are usually fine, but boost control is compromised. Drive gently and repair it soon to protect the turbo system.
Can I just clear P0033?+
It comes back until the solenoid or its circuit is fixed.
Related codes
Often seen with P0033
Read & clear P0033 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX