The issue covered by the bulletin involves a power steering noise/whine or fluid leak from the power steering pump, gear or high pressure side power steering hose during extreme low outdoor temperature operation.
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.
OBD P078B code and tailpipe testing are two different approaches to identify vehicles in need of repair. The OBD system looks for broken or malfunctioning emissions control components and oil change reset button circuit failure, while tailpipe tests sample a vehicle's exhaust to see if it is above or below certain prescribed limits. Given the robust nature of today's emissions control components, it is entirely possible for an individual component to P078B malfunction without leading to an immediate increase in emissions at the tailpipe. In such cases, other components (like the catalyst) can temporarily compensate for the part that is broken however, these other components can only do double duty for so long before they, too, begin to malfunction. In addition, OBD also monitors for P078B and other malfunctions in the fuel system problems that traditional tailpipe tests were not designed to identify. Most state and local areas also include a gas cap pressure test as part of an emission inspection.
Difficulty Level (Easy)
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Repair Time (20 Min.)
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| Cost Prediction : $ 50-100 |
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P078B is a kind of Powertrain Trouble Code
Powertrain of a modern automobile, comprising engine (with exhaust system), transmission, drive shaft, suspension and the wheels. In a motor vehicle, the term powertrain or powerplant describes the main components that generate power and deliver it to the road surface, water, or air. |
You can view according P078B DTC for your car model. We selected several models to see obd2 solutions click and view it.
Engine OBD 2 Codes website is a freeware resource center for engine trouble codes.
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