P123B Peugeot 406 Diagnostic Trouble Code

P123B Peugeot 406 code definition:
P123B is a kind of OBD-II Diagnostic P-Powertrain Diagnostic Trouble Code for Peugeot 406.

P123B Peugeot 406 is a DTC or a diagnostic trouble code. It is a check engine light code which indicates that the catalyst's system efficiency is less than the required threshold. In simple terms, it means that more pollution is added into the air than what was supposed to be because of your car. There are two wires dedicated for each coil; one is battery feed which usually comes from the distribution center, and the other one for the coil driver circuit from the PCM. The PCM grounds or ungrounds the circuit to activate or deactivate the coil.

Symptoms

Symptoms of a P123B Peugeot 406 diagnostic trouble code may include:

Carbon Buildup on O2 Sensor
Malfunction Indicator Lamp (MIL) illuminated
Hesitation upon acceleration
Rich or lean exhaust

Possible Causes :

The Mass Airflow sensor will also cause this problem. Mass Airflow circuit malfunction.
Fuel with a large percentage of sulfur will clog the DPF quickly
Some aftermarket accessories and performance modifications

Common Misdiagnoses

IC Circuit High Voltage Problem
Control Module Throttle Actuator Position Performance Problem
Air Conditioning (A/C) Clutch Feedback Circuit High Voltage Problem
Cruise Vehicle Speed/Set Speed Difference Too High Problem
PCM Stack Overrun Problem

Repair Processes :

Look for damage to the tank indicating impact that may have damaged the fuel pump or sender. Oxygen sensors signal the engine management computer the amount of oxygen present in the exhaust, which is used in determining and controlling the fuel ratio. Now, clear the codes and test-drive the vehicle to see if the code is reset.

Process Tips

Diagnostic trouble code P123B Peugeot 406 is not difficult to diagnose and repair. Thus, it always pays to have a qualified technician to look after your vehicle should this error code arise.

Diagnosing this code requires the engine to be in good running shape, without unmetered air entering the engine. If other codes that relates to misfiring condition, lean running or air entering the engine is present, then you must first fix those error codes before P123B Peugeot 406.

Fortunately, P123B Peugeot 406 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.