B1557 Diagnostic Trouble Code

B1557 is a kind of OBD-II Diagnostic B-Body Diagnostic Trouble Code.

It is considered generic because it applies to all makes and models of vehicles, although specific repair steps may be different depending on your car model.

Symptoms

Symptoms of a B1557 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
Diminished fuel efficiency

Possible Causes :

The Mass Airflow sensor is a hot wire that senses the volume of air entering the intake manifold. The computer uses this information to control fuel mixture.
Defective ECU strategies or components will prevent proper regeneration
An air leak forward of the DPF will change the sensor readings resulting in the code

Repair Processes :

Look at the plug wires to make sure they are not burnt or laying on the exhaust. Look for missing ground strap or a rusty ground where the fuel tank is grounded to the frame. Check for damage to the wiring harness connector. It should be pretty close to battery voltage (12 volts). If not, then this is the circuit that has the problem.

Process Tips

Diagnostic trouble code B1557 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 B1557.

Fortunately, B1557 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

B1557 Trouble Code For Specific Cars

B1557 Mosler Mt Camshaft Position Sensor B Circuit Malfunction
B1557 Ginetta G10 Oil Level Switch Circuit Failure
B1557 Graham Saloon Passenger Power Window Motor Circuit Failure
B1557 Gaz 24 O2 Sensor Circuit Low Voltage (Bank 1 Sensor 3)
B1557 Kia Opirus Seatbelt Driver Pretensioner Circuit Short to Ground
B1557 Alfa Romeo 22 ABS System Is Not Operational
B1557 Alfa Romeo Brera Accessory Delay Relay Coil Circuit Short To Battery