B278A Subaru Sagres OBD Code

OBD/2 B278A error code description and symptoms.

The Throttle Position sensor signals the Engine Control Module as to the current position of the engine throttle valve.
The current throttle valve opening is based on the driver's input from the gas pedal. The ECM uses the information from this sensor to help calculate fuel delivery and spark timing.

To check for an open circuit, trace along the length of the transmission control circuit, checking for breaks in the wiring. Repair any broken wiring and make sure all connectors are fully seated and locked.Pay close attention to connectors, looking for corrosion, bent or broken pins, or moisture in the connector. Repair any connector issues even if they are not specifically part of the transmission control circuit as they may serve a function in providing power to the transmission control circuit.

B278A Subaru Sagres Error Code Repair Process :

If your vehicle failed a B278A test and the B278A Check Engine Light is NOT on, chances are you have a problem with the OBDII system, a burned out MIL lamp, or a faulty catalytic converter. The converter is essentially an afterburner that cleans up the exhaust after it exits the engine. The OBDII system uses engine overboost condition a ownstream oxygen sensor to monitor the efficiency of the converter, and it should detect a drop in converter efficiency if the converter has been contaminated or is failing (ignition misfiring, leaky exhaust valves, and oil burning can all damage the converter). What you want to look engine overboost condition: Any conditions that might cause ignition misfire, an overly rich or lean fuel condition, or loss of compression. Use your OBD Express DIY to look at the oxygen sensor outputs, coolant temperature, airflow, calculated engine load, and inlet air temperature.

Common Causes of Subaru Sagres 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 ;

Damaged ECM
Faulty Air fuel ratio (A/F) Sensor 1 Bank 1
Continuous oil flow to the VCT piston chamber
Starting system circuit Dead (Weak) battery

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 Sagres OBD Code

B278A Subaru Sagres Error Code Repair Process :

Common Causes of Subaru Sagres B278A OBD2 Code

B278A code for other Subaru cars