P0423

DTC P0423, sometimes indicated as P042300 is an OBD diagnostic trouble code indicating a generic fault with the vehicle powertrain (i.e. engine and gearbox). This code identifies an error with the auxiliary emissions system causing heated catalyst efficiency below threshold (bank 1).

This code is set when the PCM detects a decrease in the efficiency of the catalytic converter below the threshold level. This may be due to a decrease in the temperature of the catalyst, a restriction in the exhaust flow, or a decrease in the exhaust gas oxygen levels.
There are several possible causes for this code, including:
-A restriction in the exhaust system
-A malfunctioning catalytic converter
-A malfunctioning oxygen sensor
-A problem with the engine tune or fuel mixture
If this code is set, the best course of action is to have the vehicle inspected by a qualified technician to determine the cause.

• P0423: Heated Catalyst Efficiency Below Threshold (Bank 1)
• P0423: Heated Catalyst Efficiency Below Threshold Bank 1
• P0423: Heated Catalyst Below Threshold (Bank 1)
• P0423: Heated catalytic converter, bank 1 – efficiency below threshold
• P0423 00: Catalyst efficiency (cylinder row 1) per mafa
• P0423 00: Heated catalytic converter, bank 1 - efficiency below threshold