Catalytic converters must be warm before they can work properly. On a cold start the PCM provides a rich mixture to keep the cold engine running.
All that extra fuel goes into the catalytic converter. But the exhaust isn't very hot, because, ah, the engine is pretty cold. GM has employed several strategies to fire up the catalytic converter quicker and reduce cold start emissions. One way is to use a secondary air pump that pumps outside air directly into the catalytic converter.
In most cases, the TCM is integrated into a single housing with the PCM. Nevertheless, the section of the module which controls (automatic) transmission function may be powered up separately. In any case, the TCM is typically powered using switched (only present with the ignition switch in the ON, start, or run position) voltage. This circuit is normally equipped with a fuse, fusible link, and/or a relay. Frequently, the PCM and TCM are powered using the same relay albeit by separate circuits. Access to a reliable vehicle information source will yield necessary details of the TCM power circuit for the specific vehicle in question.
OBD B0959 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 3-2 downshift error, 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 B0959 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 B0959 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 (Soso)
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Repair Time (30 Min.)
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Cost Prediction : $ 40-60 |
B0959 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. |
You can view according B0959 DTC for your car model. We selected several models to see obd2 solutions click and view it.