P0234

4521 - P0234

Information saved in
DDE

Fault code
4521 - P0234

Fault text
Charging pressure control, high-pressure stage, control
deviation: Charging pressure too high/negative control
deviation: Charge-air pressure too high/negative control
deviation

Fault description
Boost-pressure control monitoring. A negative control
deviation (boost pressure too high) is recognized when the
boost-control deviation is below the lower limit.
The lower limit for monitoring the boost-pressure control
deviation is derived from a program map, depends on engine
rpm and injection quantity, and lies at roughly -200 hPa.

Condition for fault identification
Test condition:
Monitoring for persistent control deviation is implemented
when the engine is in operating range 3 or 4.
- Operating range 3 is active when the injection quantity
exceeds 10 mg/hub and the engine speed is greater than
1400 1/min.
- Operating range 4 is active when the injection quantity
exceeds 100 mg/hub and the engine speed is greater than
6000 1/min.
Voltage condition:
Monitoring for persistent control deviation is implemented
when the engine is in operating range 3 or 4.
- Operating range 3 is active when the injection quantity
exceeds 10 mg/hub and the engine speed is greater than
1400 1/min.
- Operating range 4 is active when the injection quantity
exceeds 100 mg/hub and the engine speed is greater than
6000 1/min.

Condition for fault memory entry
Debounce (4000 ms)

Action in service
Engine with single-stage boost:
1. Check air-induction system for leaks.
2. Check boost pressure actuator for signs of tampering.
3. Perform mass airflow system test.
Engine with multi-stage boost:
1. Check air-induction system for leaks.
2. Check turbine control flap (tampering).
3. Check boost pressure actuator high-pressure stage
(tampering).

Fault effect and breakdown warning
Active torque reduction.
Do not drive at WOT/full throttle, component hazard
possible..
The error disables regeneration in the particulate filter.
Proceed to the nearest BMW Service facility.

Driver information
Warning light:
MIL_SVS

Service instruction
Check diagnostic trouble codes for the named components.