P122C

475F - P122C

Information saved in
DDE

Fault code
475F - P122C

Fault text
DDE: Nitrogen oxide sensor upstream of SCR catalytic
converter, line disconnection short circuit to ground: Short-
circuit

Fault description
The error is recognized when NOx sensor 1 (before SCR
converter) transmits a short circuit error (linear, binary
lambda value, NOx signal or heater circuit) via the CAN.
This is the case when at least one of the following error
conditions has been recognized:
- NOx sensor short circuit == 1
- Linear lambda short circuit == 1
- Binary lambda short circuit == 1
- Short circuit in heater == 1

Condition for fault identification
Test condition:
The following conditions must be satisfied before the NOx
sensor diagnosis function is enabled == 1
- Heater diagnosis enabled == 1
- NOx sensor heater temperature has reached specified
temperature. == 1
- No electrical malfunctions have been detected is locked.
Voltage condition:
The following conditions must be satisfied before the NOx
sensor diagnosis function is enabled == 1
- Heater diagnosis enabled == 1
- NOx sensor heater temperature has reached specified
temperature. == 1
- No electrical malfunctions have been detected is locked.

Condition for fault memory entry
Debounce (2000 ms)

Action in service
Replace wire (supply NOx sensor ECU or between NOx
sensor ECU and NOx sensor) /check plug and/or replace
NOx sensor 1 (before SCR converter).

Fault effect and breakdown warning
-

Driver information
Warning light:
MIL

Service instruction
1. Check wires and plug connections.
2. If wiring and plug connections are OK:
3. Replace NOx sensor 1 (on front side of SCR converter).