429A

429A - P02CB

Information saved in
DDE

Fault code
429A - P02CB

Fault text
DDE: Boost-pressure control, low-pressure stage, control
deviation: Charge-air pressure too low/positive control
deviation

Fault description
Monitoring of low-pressure boost pressure control. A
positive control deviation (boost pressure too low) is
recognized when the low-pressure boost-control deviation is
greater than a limit defined according to the instantaneous
operational status.
The limit for monitoring the control deviation is determined
using a program map and is based on engine speed and
injection quantity or internal torque.

Condition for fault identification
Test condition:
Monitoring for persistent control deviation is implemented
when the engine is in operating range 3 or 4 and the low-
pressure boost-pressure control is active.
- Operating range 3 is active when the injection quantity
exceeds 22 mg/hub and the engine speed is greater than
2500 1/min.
- Operating range 4 is active when the injection quantity
exceeds 35 mg/hub and the engine speed is greater than
4000 1/min.
When compliance with the above conditions is present, the
error is checked continuously once the debounce time has
elapsed.
Voltage condition:
Monitoring for persistent control deviation is implemented
when the engine is in operating range 3 or 4 and the low-
pressure boost-pressure control is active.
- Operating range 3 is active when the injection quantity
exceeds 22 mg/hub and the engine speed is greater than
2500 1/min.
- Operating range 4 is active when the injection quantity
exceeds 35 mg/hub and the engine speed is greater than
4000 1/min.
When compliance with the above conditions is present, the
error is checked continuously once the debounce time has
elapsed.

Condition for fault memory entry
Debounce (6000 ms)

Action in service
1. Check mass airflow system behind large compressor for
leaks.
2. Check throttle valve for malfunctions.
3. Check EGR valve for malfunctions.
4. Check boost pressure actuator for faults.
5. Check exhaust system for flow obstructions and leaks
(gasket between the turbines and the exhaust manifold).
6. Check compressor bypass valve for faults and sticking.
7. Check turbine control flap for faults and tight sealing
when closed.
8. Check wastegate valve for malfunctions and to ensure that
it seals when closed.

Fault effect and breakdown warning
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.