MEDIUM RISK
Common symptoms
- See page for quick checks
Cost expectations
Typical costs vary by car and region. Use this as a ballpark.
- DIY / parts: £20–£80
- Garage / labour: £80–£250
Most likely causes (ranked)
Start at the top. Rule out the common, cheap causes before expensive ones.
- Wastegate stuck
- Boost control solenoid fault
- Vacuum line routing
- Aftermarket tune mismatch
- MAP sensor error
Quick checks (fast, low-cost)
Fast checks you can do with basic tools before buying parts.
- Scan for overboost codes and requested vs actual boost.
- Inspect wastegate actuator movement.
- Check vacuum/boost lines.
- Verify tune matches hardware.
- Check MAP sensor readings.
Recommended tools
These tools make diagnosis faster and stop you buying random parts.
Related fixes
If your symptoms don’t match perfectly, check these next.
What to do next
- Avoid hard boost to protect engine/turbo.
- Fix control hardware before tuning.