Turbo/Supercharger Boost Control Circuit High
Code P0048 indicates that the Powertrain Control Module (PCM) has detected a voltage signal from the turbocharger or supercharger boost control solenoid circuit that is higher than the expected range. This solenoid regulates boost pressure by controlling vacuum or pressure to the wastegate actuator. A high voltage condition typically points to a short to power, faulty solenoid, or wiring issues. This can lead to overboost conditions, reduced engine performance, or limp mode activation.
1. Most Common Causes
- Short to power in the boost control solenoid circuit
- Faulty turbocharger/supercharger boost control solenoid
- Damaged wiring or connector in the solenoid circuit
- Corroded or loose electrical connections
- Faulty PCM (rare)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine power or limp mode
- Overboost or underboost conditions
- Poor acceleration and throttle response
- Excessive black smoke from exhaust
3. Step-by-Step Diagnosis
Step 1: Scan for additional codes and freeze frame data to confirm P0048.
Step 2: Visually inspect the boost control solenoid and its wiring for damage, corrosion, or loose connections.
Step 3: Use a multimeter to check for a short to power or ground in the solenoid circuit.
Step 4: Test the solenoid resistance and compare to manufacturer specifications.
Step 5: If wiring and solenoid are okay, test the PCM output signal to the solenoid.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as the vehicle may enter limp mode or experience overboost, which can damage the turbocharger or engine.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, including parts and labor. The boost control solenoid itself costs $50-$150, plus diagnostic and labor fees.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.