Check U0121 Fault Code
When you check engine light came on code U0121 the reason should be Engine Light ON (or Service Engine Soon Warning Light). However your vehicle's manufacturer may have a different definition for the U0121 OBD-II Diagnostic Network (U) Trouble Code. So you should chech it on our car models.
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Parts or components should not be replaced with reference to only a U0121 DTC. The vehicle service manual should be consulted for more information on possible causes of the fault, along with required testing. |
U0121 Possible Fix :
If there's a part that needs repairing, leave it to the professionals. Unless of course, you're confident that you can conduct all these repairs at home. You'll need relatively expensive replacement equipment and tools for this though.
U0121 OBD-II Diagnostic Network (U) Trouble Code DescriptionU0121 OBD-II Trouble Code Modules connected to the high speed General Motor Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commReason For U0121 CodeThe reason of U0121 OBD-II Fault Code Check is U0121 Lost Communication With Electronic Brake Control Module. |
U0121 Solution:
Disconnected, dirty or fouled spark plugs are common causes for engines that won't start. Spark plugs typically need to be replaced every season or 25 hours of use. You should also check that the spark plug gap is set properly. If your spark plugs look good, problems with your ignition system can also preventing a spark. These can range from a faulty spark plug lead, shorted kill switch or flywheel key damage.
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What does fault code U0121 mean ?
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How to Clear U0121 Trouble Code
An OBD 2 scanner is the best and safest way to erase a DTC from your car's system. This scanner communicates with the car's computer and instructs the computer to erase the code. It does not change or tweak the settings from inside the car or its systems.