B1549 Bristol 401 Diagnostic Trouble Code

B1549 Bristol 401 code definition:
B1549 is a kind of OBD-II Diagnostic B-Body Diagnostic Trouble Code for Bristol 401.

B1549 Bristol 401 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 B1549 Bristol 401 diagnostic trouble code may include:

Possible spark knock (detonation / pre-ignition)
Poor fuel economy
The engine oil will exhibit dilution from the ECUs attempts to increase engine temperature. Some vehicles advance the fuel injection timing slightly after top center to afterburn a small amount of fuel to increase exhaust temperatures. Some of this fuel enters the crankcase. When the ECU determines the necessity to regenerate the DPF, the service life of the oil be shortened significantly
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
Defective ECU strategies or components will prevent proper regeneration

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. If the scan tool has that capability, and the scan tool can operate the IMRC valves, then the problem is either resolved and a simple code clearing is all that's left or a new PCM would be called for.

Process Tips

Diagnostic trouble code B1549 Bristol 401 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 B1549 Bristol 401.

Fortunately, B1549 Bristol 401 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.