Turbo/Super Charger Turbine Overspeed
This code has varied definitions, depending on the manufacturer. The code is generated when the Engine Control Unit (ECU) detects an abnormal reading in the turbocharger or supercharger overspeed sensor circuit.
Generally, the P0049 code is related to the circuit and sensor on the turbo/super charger which determines the actual speed of the unit. The fault indicates that the turbo/super charger is turning too fast, which is not a common situation, so the cause is usually related to the wiring or speed/boost sensor. Also, the boost control valve or waste gate may be stuck shut.
If the P0049 code returns, the mechanic should follow these test procedures:
Inspect the turbo/super charger system, especially for the solenoid valve and wastegate being inoperative or stuck
Inspect the wiring on the boost sensor/speed sensor and related wiring for loose connections, damaged wiring, or a faulty sensor
Check the boost pressure during operation and driving for a normal range of 9 to 14 PSI pressure to insure it is not too high
Inspect the turbo charger to ensure no damage or part failures
Do not replace any component, assuming it is bad, without inspecting the system. The actual tested boost pressure is the best place to start to prevent common misdiagnosis.
This code is very serious and is usually preceded by the engine warning light coming on. It can accompanied by unusual engine noises including high pitched, rattling, hissing or unusual sounds. It should be diagnosed as soon as possible to prevent engine internal damage, or turbocharger failure. The 2012 Mitsubishi Eclipse spyder can run very erratically, backfire, have rich or lean fuel consumption problems, and operate in over boost conditions.
Minimize your driving until the problem can be repaired. If your 2012 Mitsubishi Eclipse spyder operates very poorly, do not drive it further.
Often times, if the engine warning light comes on immediately at start up, the OBD- II system can be reset and your 2012 Mitsubishi Eclipse spyder will operate normally.
Finding the best path to repair for the P0049 code is often confusing, and the notion of turbo/super charger overspeed can have many associated problems that are the cause. Overspeed of the turbo/supercharger is actually rare and is more accurately described as an "over boost situation". It is quite possible that, if the bypass valve or wastegate is stuck closed, an overspeed or over boost condition can exist under full load conditions.
Often, an overspeed situation can be repaired by addressing a sensor or wiring issue. Older 2012 Mitsubishi Eclipse spyders with more miles on them tend to have failing sensors, causing false output signals to the ECU.
Many 2012 Mitsubishi Eclipse spyders with mileage over 100,000 have momentary sensor problems that usually occur during start up or prolonged stress situations on the drive train. If the engine warning light comes on and your 2012 Mitsubishi Eclipse spyder seems to be operating normally, the OBD-II system can be reset using the scanner and the problem may not reoccur. This is why it is important to verify the fault and reset it before doing any repairs.