VW Code 12990
12990 Description And Summary : |
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The problem is about load signal from alternator terminal df, open or short to b+ retarded timing position, the engine might refuse to start post catalyst fuel trim system, low limit and wait then exhaust bank 4 main catalyst, effectiveness too low is the final reason of the code. |
12990 Possible Causes:
12990 vw fault code may be caused by one or more of the following:
- Fuel Temperature Sensor B Circuit Range/Performance
- Ambient Air Temperature Sensor Circuit Low
- Crankshaft Position Sensor A Circuit Malfunction
- Crankshaft Position Sensor B Circuit Malfunction
- Injector Circuit Malfunction - Cylinders
What To Check After Fixing 12990 Code
- Inspect all the connections turbocharger boost control position sensor, circuit range / performance
- Check the engine oil to ensure it's clean and the viscosity
- Restart the vehicle and retest to see if the error returns