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.
Regardless of the design though, the purpose of all clutch actuating systems is to improve the driving experience by removing the need for manual clutch operation by the driver. Computer-controlled clutch actuating systems work particularly well in dual clutch systems where one clutch controls gear changes of even-numbered gear ratios, and a second clutch that controls gear changes of odd-numbered ratios.
If your air suspension rr air spring/shock solenoid output circuit short to ground check engine light is illuminated, it's best to take it in for diagnostic testing, which can feel like a hassle. Because while the lights vary in appearance from vehicle to vehicle, all have the same basic meaning: There's a problem with the car's emissions system. The on-board diagnostics system U251U and engine control unit are in charge of monitoring a bunch of different air suspension rr air spring/shock solenoid output circuit short to ground, and if they get a reading that's a little out of whack, up pops the check engine light.
Difficulty Level (Easy)
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Repair Time (45 Min.)
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| Cost Prediction : $ 80-120 |
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U251U is a kind of Network Trouble Code
U-code indicates that engine communication errors and shows lost communication with engine parts.U-Codes are fairly straight forward, given all of the articles and technical publications that have been written regarding these problematic codes. In most cases, it just comes down to identifying the module that isn't communicating with the other modules on the CAN bus line for whatever reason. |
You can view according U251U 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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