B278A Subaru G3x Justy OBD Code

OBD/2 B278A error code description and symptoms.

HO2S Sensor Circuit Malfunction (HO2S-11) During testing the HO2S Heaters are checked for opens/shorts and excessive current draw.
The test fails when current draw exceeds a calibrated limit and/or an open or short is detected. Short to VPWR in harness or HO2S. Water in harness connector. Open VPWR circuit. Open GND circuit. Low battery voltage. Corrosion or poor mating terminals and wiring Damaged HO2S heater. Damaged PCM.

As long as the throttle plate remains closed, the idling speed and quality is controlled by the PCM via the idle control valve, and as can be seen from the above it should be clear that idle control on a gasoline engine is a complex affair. For instance, if the engine is started in sub-zero temperatures, the PCM will command the idling control valve to allow less air to enter the engine to enrich the air/fuel mixture to create a condition which is roughly analogous to how chokes worked on carburetted engines to control idling in cold weather.

B278A Subaru G3x Justy Error Code Repair Process :

When you turn on the ignition, the Service Engine Soon or Check Engine B278A light should flash briefly, indicating that the OBD system is ready to scan your vehicle for any malfunctions. After this brief flash, the light should stay off while you drive as long as no problems are detected. If engine overboost condition so, you'll be glad to know that your vehicle is equipped with an early warning system that could save you time, money, and fuel in addition to helping protect the engine overboost condition.

Common Causes of Subaru G3x Justy B278A OBD2 Code

A common cause of code B278A is the failure of Engine Overboost Condition, but there are several other possible causes as well, such as ;

Exhaust tube
Faulty starter motor
Intake Valve Timing Control Solenoid Valve harness is open or shorted
Three way catalyst converter Bank 1

B278A is a kind of Body Trouble Code

Auto body problems aren't always easy to spot. Diagnosing auto body problems sometimes requires a little know-how. In this section you'll find articles dedicated to teaching you how to diagnose auto body problems.

Engine OBD 2 Codes website is a freeware resource center for engine trouble codes.

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B278A Subaru G3x Justy OBD Code

B278A Subaru G3x Justy Error Code Repair Process :

Common Causes of Subaru G3x Justy B278A OBD2 Code

B278A code for other Subaru cars