C2839 Subaru R2 Diagnostic Trouble Code

C2839 Subaru R2 code definition:
C2839 is a kind of OBD-II Diagnostic C-Chassis Diagnostic Trouble Code for Subaru R2.

C2839 Subaru R2 is described as Oxygen Sensor Circuit No Activity Detected (Bank 1, Sensor 1). This means there's a problem in the front oxygen sensor on Bank 1, as the O2 sensor is inactive. As you drive and when specific conditions are slowly met, the vapors will gradually purge from the charcoal canister and will get burned within your engine.

Symptoms

Symptoms of a C2839 Subaru R2 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
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected

Possible Causes :

Fuel with a large percentage of sulfur will clog the DPF quickly
The Mass Airflow sensor will also cause this problem. Mass Airflow circuit malfunction.
Defective ECU strategies or components will prevent proper regeneration

Common Misdiagnoses

IC Circuit High Voltage Problem
Control Module Throttle Actuator Position Performance Problem
Air Conditioning (A/C) Clutch Feedback Circuit High Voltage Problem
Cruise Vehicle Speed/Set Speed Difference Too High Problem
PCM Stack Overrun Problem

Repair Processes :

Look for damage to the tank indicating impact that may have damaged the fuel pump or sender. Look at the plug wires to make sure they are not burnt or laying on the exhaust. Now, clear the codes and test-drive the vehicle to see if the code is reset.

Process Tips

Diagnostic trouble code C2839 Subaru R2 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 C2839 Subaru R2.

Fortunately, C2839 Subaru R2 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.