P045F

478E - P045F

Information saved in
DDE

Fault code
478E - P045F

Fault text
DDE: Low-pressure exhaust-gas recirculation valve,
plausibility: mechanically faulty near closed position

Fault description
If a positive or negative deviation in the low-pressure EGR
control system remains present for a period of 3 s, and it has
proven impossible to resolve this issue despite attempts to
free the valve with the low-pressure EGR actuator in the
intervening period, the system recognizes the low-pressure
EGR valve as sticking in its closed position.
For this the actual pulse-duty factor of the low-pressure
EGR actuator must be less than 5 % or the specified pulse-
duty factor of the low-pressure EGR actuator greater than
EGRVlv_rJamVlvOpnDemMax_C.
A counter is incrementalized in response. This deactivates
monitoring for persistent control deviation.
A diagnostic trouble code is logged when the counter
reaches the limit value 6.

Condition for fault identification
Test condition:
The monitoring function is active only when the monitoring
function for persistent control deviation in the low-pressure
EGR control is also active and a persistent control deviation
has already been detected.
Voltage condition:
The monitoring function is active only when the monitoring
function for persistent control deviation in the low-pressure
EGR control is also active and a persistent control deviation
has already been detected.

Condition for fault memory entry
-Debounce time for detection of a positive control deviation
5000 ms+ time for break-away attempts during persistent
control deviation 3 s.
Or:
Time for recognition of a negative control deviation error
5000 ms+ time during which the enable function is activated
(3 s).

Action in service
1. Check low-pressure EGR valve.
2. Replace sensors.
3. Replace low-pressure EGR valve.

Fault effect and breakdown warning
-

Driver information
Warning light:
MIL

Service instruction
none