P128F Alvis Td Diagnostic Trouble Code

P128F Alvis Td code definition:
P128F is a kind of OBD-II Diagnostic P-Powertrain Diagnostic Trouble Code for Alvis Td.

P128F Alvis Td is described as Fuel System Too Rich, which basically means bank 1's oxygen sensor has detected a rich condition of fuel. This means there's not enough oxygen in the exhaust from too much fuel being delivered into the air and gas mixture for combusion. Other symptoms that may indicate this problem are when the Check Engine Light illuminates and when there is a visible lack of engine power.

Symptoms

Symptoms of a P128F Alvis Td diagnostic trouble code may include:

The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.
Faulty PCM
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected
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
An air leak forward of the DPF will change the sensor readings resulting in the code

Common Misdiagnoses

Vehicle Speed Output Circuit Problem
Cruise Control Servo Indicates Low Problem
A/C System High Pressure High Temperature Problem
PCM Stack Overrun Problem
Transmission Control Module Reprogrammable Memory 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. Pack the connector cavity with dielectric silicone compound (same stuff they use for light bulb sockets and spark plug wires) and reassemble.

Process Tips

Diagnostic trouble code P128F Alvis Td 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 P128F Alvis Td.

Fortunately, P128F Alvis Td is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.