Turbocharger/Supercharger Boost Control A Circuit High
What it means
P0048 means the engine computer sees an abnormally high voltage on the control circuit for the turbo or supercharger boost control solenoid. That points to an electrical fault in the solenoid or its wiring rather than the turbo itself. With boost no longer controlled properly, the engine may drop into reduced-power limp mode or, less often, overboost — which is why it should be addressed before hard driving.
Can I keep driving? Usually still drivable, but boost control is unreliable — you may get reduced power or limp mode, and occasionally overboost, so have it checked before hard driving.
Common symptoms
What you'll notice
- Check-engine light on
- Reduced power or limp-home mode
- Boost pressure too high (overboost) or too low
- Turbo lag or hesitation under acceleration
Common causes
Most likely first
- Faulty turbo/supercharger boost control solenoid (wastegate or vacuum solenoid)Likely
- Short-to-voltage, open, or damaged wiring in the solenoid control circuitCommon
- Loose or corroded electrical connector at the solenoidCommon
- Failed PCM/ECM (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data, confirm the code, and inspect the boost control solenoid connector and wiring for shorts or damage.
- Test the solenoid's resistance and check its power and ground against spec.
- Repair any damaged wiring or corroded connections.
- Replace the boost control solenoid if it fails testing.
- Re-check for related boost sensor codes and clear; replace the PCM only as a last resort.
FAQ
Quick answers
Is it safe to drive with P0048?+
Can I just clear P0048?+
Related codes
Often seen with P0048
Read & clear P0048 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.