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.
At this point we are assuming that the fuses and relays are good. You will need to locate the PCM/TCM and the power input signal circuit using your vehicle information source. Unplug the connector from the PCM/TCM, place the ignition switch in the ON position, and probe the appropriate circuit with the positive test lead of the DVOM.
When you turn on the ignition, the Service Engine Soon or Check Engine U228D light should flash briefly, indicating that the OBD system is ready to scan your vehicle for any malfunctions. After this brief flash, the light should stay off while you drive as long as no problems are detected. If speed wheel sensor lr coherency fault so, you'll be glad to know that your vehicle is equipped with an early warning system that could save you time, money, and fuel in addition to helping protect the speed wheel sensor lr coherency fault.
Difficulty Level (Easy)
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Repair Time (20 Min.)
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Cost Prediction : $ 30-110 |
U228D 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 U228D DTC for your car model. We selected several models to see obd2 solutions click and view it.