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U0121 Engine Trouble Code

Meaning of U0121 engine trouble code is a kind of network trouble code and U0121 if your catalytic convertor fails completely, you eventually won't be able to keep the car running. Your gas mileage will also be terrible, so you should try and fix it as soon as you can. Unfortunately, the average replacement cost is around $2,000 and you can't do it yourself unless you're an experienced mechanic.

U0121 Fault Symptoms :

  1. Check engine light comes on
  2. Engine stalling or misfiring
  3. Engine performance issues
  4. Car not starting
If one of these reasons for U0121 code is occuring now you should check U0121 repair processes.
Now don't ask yourself; What should you do with U0121 code ?
The solution is here :

U0121 Possible Solution:

U0121 Engine

The crankshaft sensor signals the fuel injection computer or the ignition control when the cylinders are firing. This causes the ignition coil to provide a spark and the injector to inject fuel into each cylinder at the right time.If either sensor isn't working correctly, the car will run rough and the engine will be less efficient. In later car models, the car's computer can usually keep the vehicle running, but the engine warning light on the dashboard goes on to warn the driver.

U0121 Code Meaning :

U 0 1 2 1
OBD-II Diagnostic Network (U) Trouble Code For Engine Intake Valve Control Solenoid Circuit Low Fuel Rail/System Pressure - Too High Turbocharger Boost Sensor A Circuit Low Crankshaft Position Sensor A Circuit Low Input

The catalytic converter has an oxygen sensor in front and behind it. When the vehicle is warm and running in closed loop mode, the upstream oxygen sensor waveform reading should fluctuate.

U0121 OBD-II Diagnostic Network (U) Trouble Code Description

U0121 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 comm U0121 code.

Main reason For U0121 Code

The reason of U0121 OBD-II Engine Trouble Code is Fuel Rail/System Pressure - Too High.

U0121 DTCs may also be triggered by faults earlier down the line. For example, a dirty MAF sensor might be causing the car to overcompensate in its fuel-trim adjustments. As a result, oxygen sensors are likely to report fuel mixture problems.