P0422moderate severityPowertrain
Main Catalyst Efficiency Below Threshold (Bank 1)
on 2007 Ram 3500 5.9L I6 Cummins · 4WD
What this code means
The PCM determined the main catalytic converter on bank 1 is not reducing emissions efficiently. This is usually judged by comparing upstream and downstream oxygen sensor readings.
Symptoms
- Check engine light on
- Failed emissions test
- Reduced fuel economy
Common causes
- Failed catalytic converter
- Faulty downstream O2 sensor
- Exhaust leak
- Engine misfire or fuel issue
Diagnostic steps
- Scan and confirm P0422
- Compare upstream and downstream O2 data
- Inspect exhaust for leaks
- Test catalyst efficiency
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Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0005
Fuel Shutoff Valve A Control Circuit/Open
P0006
Fuel Shutoff Valve A Control Circuit Low
P0007
Fuel Shutoff Valve A Control Circuit High
P0008
Engine Position System Performance - Bank 1
P0009
Engine Position System Performance - Bank 2
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1