448B - P2A00 (DDE)

448B - P2A00

Information saved in
DDE

Fault code
448B - P2A00

Fault text
DDE: Oxygen sensor: Oxygen concentration implausibly
low (at part load)

Fault description
Plausibility check of measured vs. calculated oxygen sensor
O2 concentration at part-load with EGR control active. The
diagnostic trouble code is logged when the measured O2
concentration is less than the sum of the calculated O2
concentration and a tolerance range defined based on
operating point.

Condition for fault identification
Test condition:
The following conditions must be present for the plausibility
check:
- The plausibility check is enabled.
- The effects of injection quantity on O2 concentration are
clear.
- The O2 concentration is
- The calculated O2 concentration is stationary.
The operating point for the part-load plausibility check is
enabled when:
- The engine speed lies between 590 1/min and 980 1/min.
- The fuel injection rate lies between 4 mg/hub and
328 mg/hub.
- The air mass lies between 180 mg/Hub and 600 mg/Hub.
- The EGR must be deactivated in coasting/overrun mode.
- the EGR overrun monitoring function must be enabled for
full throttle.
- The fuel tank cannot be empty.
- The battery voltage is higher than 10700 mV.
- No thermal particulate filter regeneration has been
requested.
Once all of the above conditions have been satisfied the sum
total air mass is determined by integrating the mass airflow
in the current engine operating point.
The cumulative value must be above the limit value
LSU_mAirPlausEna_CA [1] for full load (or
LSU_mAirPlausEnaTst_CA#1 if the service test diagnosis is
active).
The integration is restarted when one of the activation
conditions indicated above is not satisfied.
The check runs continuously in a 20 ms grid.
Voltage condition:
The following conditions must be present for the plausibility
check:
- The plausibility check is enabled.
- The effects of injection quantity on O2 concentration are
clear.
- The O2 concentration is
- The calculated O2 concentration is stationary.
The operating point for the part-load plausibility check is
enabled when:
- The engine speed lies between 590 1/min and 980 1/min.
- The fuel injection rate lies between 4 mg/hub and
328 mg/hub.
- The air mass lies between 180 mg/Hub and 600 mg/Hub.
- The EGR must be deactivated in coasting/overrun mode.
- the EGR overrun monitoring function must be enabled for
full throttle.
- The fuel tank cannot be empty.
- The battery voltage is higher than 10700 mV.
- No thermal particulate filter regeneration has been
requested.
Once all of the above conditions have been satisfied the sum
total air mass is determined by integrating the mass airflow
in the current engine operating point.
The cumulative value must be above the limit value
LSU_mAirPlausEna_CA [1] for full load (or
LSU_mAirPlausEnaTst_CA#1 if the service test diagnosis is
active).
The integration is restarted when one of the activation
conditions indicated above is not satisfied.
The check runs continuously in a 20 ms grid.

Condition for fault memory entry
Event debounced (100) The diagnostic trouble code is
logged when at least 100 error events have been counted.
During service test diagnosis the debounce is divided by 2.

Action in service
1. Check exhaust system for leaks.
2. Check wires and plug connections.
3. If wiring and plug connections are OK:
Replace oxygen sensor.

Fault effect and breakdown warning
-

Driver information
Warning light:
MIL

Service instruction
none