4C6C - P244C (DDE)

4C6C - P244C

Information saved in
DDE

Fault code
4C6C - P244C

Fault text
DDE: Exhaust-gas temperature controller, control deviation:
Deviation from setpoint temperature value too high (current
manipulated variable of outer control loop at maximum
value)

Fault description
The exhaust-gas temperature control system relies on
different control parameters (adjustment of throttle valve,
secondary injection, etc.) to regulate the temperature of the
exhaust gas to a specified level (roughly 620�C) during
regeneration of the particulate filter. The external closed-
loop control circuit regulates the exhaust-gas temperature of
the particulate filter. The diagnostic trouble code is logged
when the control deviation of the outer control circuit rises
above a limit defined according to operating point and the
current control variable of the outer control circuit lies
above the threshold 1.

Condition for fault identification
Test condition:
The test routine runs when the following conditions are
satisfied:
- The exhaust-gas temperature controller's control variable
has reached its maximum.
- The outer exhaust-gas temperature controller must be
active.
- The current operating point must be valid.
- The actual temperature of the inner exhaust-gas control
circuit must exceed 10 s.
The check runs continuously in a 100 ms grid.
Voltage condition:
The test routine runs when the following conditions are
satisfied:
- The exhaust-gas temperature controller's control variable
has reached its maximum.
- The outer exhaust-gas temperature controller must be
active.
- The current operating point must be valid.
- The actual temperature of the inner exhaust-gas control
circuit must exceed 10 s.
The check runs continuously in a 100 ms grid.

Condition for fault memory entry
Debounce (20000 ms)

Action in service
Check the following potential problem sources:
- Mass airflow sensor contaminated / implausible air mass
data.
- Pre-catalyst exhaust-gas temperature is implausible.
- Exhaust-gas temperature upstream from particulate filter is
implausible. With engine cold check mutual plausibility of
exhaust-gas temperatures.
- Fuel quantity drift at injectors.
Check for DTC entries related to the indicated components,
repair faults.

Fault effect and breakdown warning
-

Driver information
Warning light:
MIL

Service instruction
none