P0046moderate severityPowertrain
Turbo/Supercharger Boost Control Solenoid Circuit Range/Performance
on 1998 BMW 528i 2.8L I6 M52 · RWD
What this code means
The boost control solenoid is not responding within expected parameters.
Symptoms
- Check Engine Light
- Overboosting or underboosting
- Reduced power
- Surging
Common causes
- Sticking solenoid
- Vacuum leak
- Wastegate stuck
- Boost pressure sensor fault
Diagnostic steps
- Monitor boost pressure vs commanded
- Test solenoid operation
- Check vacuum lines
- Inspect wastegate
Repair notes
Replace solenoid or repair wastegate.
🔌 Don't have a code reader?
Any of these will read and clear this code — pick by how deep you want to go.
Bluetooth code reader (~$25)
Veepeak OBDCheck BLE →
Pairs with your phone — reads and clears codes, live data.
Serious DIY (~$100)
BlueDriver Pro →
Enhanced codes (ABS, airbag, TPMS) plus repair reports.
Shop-grade tablet (~$300+)
Autel MaxiCOM MK808S →
Bidirectional tests, service resets, all systems.
As an Amazon Associate, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.
Other Powertrain codes on this vehicle
29CC
Misfire Cylinder 1
29CD
Misfire Cylinder 2
29CE
Misfire Cylinder 3
29CF
Misfire Cylinder 4
29D0
Misfire Cylinder 5
29D1
Misfire Cylinder 6
29D2
Misfire Cylinder 7
29E0
Lambda Additive/Idle Adaptation Limit, Bank 1
29E1
Lambda Additive/Idle Adaptation Limit, Bank 2
29E2
Lambda Multiplicative Part-Load Adaptation Limit, Bank 1