4BCC - P21A8 (DDE)

4BCC - P21A8

Information saved in
DDE

Fault code
4BCC - P21A8

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

Fault description
Monitoring of both passive tank level sensors. The DTC is
logged when the physical sensor signal is between 35 % and
45 %.

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. Use diagnostic system to check sensor signal.
4. Replace passive tank.

Fault effect and breakdown warning
-

Driver information
Warning light:
MIL

Service instruction
Measure the resistance levels at the fluid-level sensor
between pins 1 and 2, and between pins 3 and 4. The tank
must be empty for this measurement.
Normal resistance with empty tank: 10 kOhm.
Resistance levels in excess of 12 kOhms indicate that the
fluid-level sensor is defective.