Engine Controls System: 2789

2789 - P0420

Information saved in
DME

Fault code
2789 - P0420

Fault text
Catalytic-converter conversion, bank 1

Fault description
Catalyst System Efficiency Below Threshold (Bank 1)

Condition for fault identification
Test condition:
Diagnosis value above threshold
K_KAT_OBD_WERT_MAX
Terminal condition: Engine running - Condition idle or part-
load
Voltage condition:
none

Condition for fault memory entry
none

Action in service
1. Check exhaust system for leaks /2. No faults related to
oxygen sensor or fuel system or VANOS should be present
/3. Conduct oxygen sensor test routines, even if no oxygen
sensor fault is present./ 4. Replace catalytic conveter near
engine

Fault effect and breakdown warning
MIL on after engine runs 2x

Driver information
Warning light:
MIL

Service instruction
none