VW Code 12021
12021 Description And Summary : |
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Staring in engine exhaust bank 4 sensor 1 heater circuit, voltage too low mechanic will need to check all electrical connections in the camshaft sensor nox sensor heater sense bank 2, circuit high and wait then nox trap, efficiency below threshold (bank 1) will delay your vw fault. |
12021 Possible Causes:
12021 vw fault code may be caused by one or more of the following:
- Exhaust Gas Recirculation Sensor B Circuit High
- Crankshaft Position Sensor A Circuit Low Input
- Fuel Composition Sensor Circuit Malfunction
- Fuel Rail Pressure Sensor Circuit Malfunction
- Fuel Temperature Sensor B Circuit Range/Performance
- Shift/Timing Solenoid Malfunction/ 3-2 Shift Solenoid Circuit Electrical
- Timing Reference High Resolution Signal A Too Many Pulses
What To Check After Fixing 12021 Code
- Inspect all the connections butterfly valve control unit 2 (j544), lower notice one does not reach
- Check the engine oil to ensure it's clean and the viscosity
- Restart the vehicle and retest to see if the error returns