4B81 - P0402 (DDE)

4B81 - P0402

Information saved in
DDE

Fault code
4B81 - P0402

Fault text
DDE: Exhaust-gas recirculation-rate control, control
deviation: Exhaust-gas recirculation rate too high/negative
control deviation

Fault description
The diagnostic trouble code is logged in the ECU when the
exhaust-gas recirculation system flow rate control's positive
control deviation exceeds a limit defined based on the
operating point.

Condition for fault identification
Test condition:
In normal operation the check runs every 20 ms when the
specified value priority assignment is set to flow rate and no
other errors related to the exhaust-gas recirculation have
been detected.
Voltage condition:
In normal operation the check runs every 20 ms when the
specified value priority assignment is set to flow rate and no
other errors related to the exhaust-gas recirculation have
been detected.

Condition for fault memory entry
Debounce (3000 ms)

Action in service
Check the following potential problem sources:
1. Leak in mass airflow system between mass-airflow sensor
and compressor.
2. Contaminated air filter.
3. Defective mass-airflow sensor.
4. Swirl valves sticking in closed position.
5. Carbon deposits on intake valves.
6. Defective throttle valve (in combination with throttle
valve faults).
7. Defective EGR valve (in combination with EGR valve
faults).
8. Defective turbocharger (in combination with turbocharger
faults).
Applies to engines with single-stage boost: Conduct mass
airflow system test.

Fault effect and breakdown warning
Proceed to the nearest BMW Service facility.

Driver information
Warning light:
MIL_SVS

Service instruction
Check diagnostic trouble codes for the named components.