4BCB - P21A8 (DDE)

4BCB - P21A8

Information saved in
DDE

Fault code
4BCB - P21A8

Fault text
DDE: Reducing-agent passive-tank fill-level sensor, signal:
Sensor monitoring fault

Fault description
Plausibility check on passive tank reduction agent level.
The level sensor's evaluation circuit transmits the
information "all sensors wet" immediately followed by "all
sensors dry" within the period 70 s. The diagnostic trouble
code is logged when the status change is not completed
within this period.
The diagnostic trouble code is also logged when the raw
level value does not lie between SCR_rUPasTnkLvlMin_C
and SCR_rUPasTnkLvlMax_C.

Condition for fault identification
Test condition:
The test routine is executed continuously.
Voltage condition:
The test routine is executed continuously.

Condition for fault memory entry
Debounce (2000 ms)

Action in service
1. Check wires and plug connections.
2. If wiring and plug connections are OK:
3. Replace electronic processing circuitry for the passive
tank's fluid-level sensors.

Fault effect and breakdown warning
-

Driver information
Warning light:
MIL

Service instruction
none