KlaroP0423
MODERATEHeated Catalyst Efficiency Below Threshold (Bank l)
What this code means
Heated Catalyst Efficiency Below Threshold (Bank l). Catalytic converter, exhaust gas recirculation, particulate filter, fuel vapour. These faults rarely leave you stranded, but they fail the roadworthiness test and become expensive if left alone.
How to read this code
- PPowertrain
- 0standardised code
- 4Emission controls
- 23P0423
The letter P names the system: Powertrain. The digit 0 that follows marks a standardised code, shared by all manufacturers code. The next digit, 4, locates the fault: emission controls.
What to do
Have it checked this week. The car remains usable, but the fault will not clear itself and will fail the roadworthiness test.
Clearing a code switches the light off but repairs nothing: if the fault remains, the code comes back.