P0431moderate severityPowertrain
Warm Up Catalyst Efficiency Below Threshold Bank 2
on 1996 Lexus LS 400 4.0L V8 · RWD
What this code means
Bank 2 warm-up catalyst efficiency is below threshold.
Symptoms
- Check Engine Light
- Failed emissions
Common causes
- Worn catalyst
- Rich running during warmup
- O2 sensor issue
Diagnostic steps
- Monitor catalyst
- Compare O2 signals
- Check exhaust
Repair notes
Replace warm-up catalyst if confirmed.
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
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0011
Intake Camshaft Position Timing Over-Advanced Bank 1
P0012
Intake Camshaft Position Timing Over-Retarded Bank 1
P0013
Exhaust Camshaft Position Actuator Circuit/Open Bank 1
P0014
Exhaust Camshaft Position Timing Over-Advanced Bank 1
P0015
Exhaust Camshaft Position Timing Over-Retarded Bank 1