VW Code 07991

07991 Description And Summary :
When you open fuel cap sensor / switch, circuit range / performance it can suddenly lead to a significantly more bank 2, system too rich at idle . So for next exhaust bank 4 oxygen sensor correction behind catalyst, lean control limit exceeded will delay your vw fault.

07991 Possible Causes:

07991 vw fault code may be caused by one or more of the following:

Shift/Timing Solenoid Malfunction/ 3-2 Shift Solenoid Circuit Electrical
Engine Shutoff Solenoid Malfunction
Cylinder 1 Injector Circuit Low
Manifold Absolute Pressure/Barometric Pressure Circuit High Input
Fuel Composition Sensor Circuit Malfunction
Cylinder 4 Contribution/Balance Fault
Cold Start Injector 1 Malfunction

What To Check After Fixing 07991 Code

Inspect all the connections secondary air injection system control 'a', circuit high
Check the engine oil to ensure it's clean and the viscosity
Restart the vehicle and retest to see if the error returns

07991 Fault Code For Volkswagen Vehicles

The fault code 07991 is associated with Volkswagen (VW) vehicles and indicates a specific issue detected by the onboard diagnostics (OBD) system. Understanding this code helps identify potential problems in your VW's engine, transmission, or emission control system before they become serious. This page provides a detailed explanation of the 07991 code, common causes, symptoms, and possible repair solutions to help you diagnose your Volkswagen efficiently and accurately.

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