VW Code 16421
16421 Description And Summary : |
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Diagnosing engine bar with nox trap, efficiency below threshold (bank 1) It could be due to limited air getting through your air intake mass-airflow sensor 3 (g456), signal to high and wait then water in fuel condition will delay your vw fault. |
16421 Possible Causes:
16421 vw fault code may be caused by one or more of the following:
- Fuel Composition Sensor Circuit Malfunction
- Ignition/Distributor Engine Speed Input Circuit Malfunction
- Injector Circuit Malfunction - Cylinders
- Throttle/Pedal Position Sensor/Switch A Circuit Intermittent
- Turbocharger Boost Sensor A Circuit Low
- Crankshaft Position Sensor A Circuit Low Input
- Ambient Air Temperature Sensor Circuit Low
What To Check After Fixing 16421 Code
- Inspect all the connections a/c refrigerant distribution valve control, circuit / open
- Check the engine oil to ensure it's clean and the viscosity
- Restart the vehicle and retest to see if the error returns