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P0421 Engine Diagnostic Code For Audi A8
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P0421 engine code for Audi A8 provides below are generic codes that may not apply to all vehicles. Audi A8 manufacturer uses specific Audi A8 diagnostic code that are different from the codes shown below. Foreign vehicles may also use DTC codes different from the generic DTC codes. |
To solve P0421 problem, you'll have to remove the muffler, crankcase and other components blocking the valve chamber. Then, remove the cylinder head bolts (label for easy re-installation) Adjust the jaws of the valve spring compressor until they touch the top and bottom of the valve chamber Push the tool in to compress the spring and tighten the jaws Remove the retainers and lift out the valves , compressors and springs
P0421 Diagnostic Trouble Code For Audi A8 Meaning
| 0 | 0 | 4 | 21 |
|---|---|---|---|
| Powertrain Problem | SAE - Generic | Auxiliary Emission Controls | 21 Engine Fault Code |
How to fix P0421 engine diagnostic code For Audi A8 ?
Starting letter 0 diagnostic code shows that there are problems in engine, transmission and emissions systems.
If your "Check Engine Light" is on, it means your vehicle has one or more OBD II Trouble Codes so you have to check your engine diagnostic code tool.
If your vehicle is an older model with a non-electronic Auxiliary Emission Controls, you can check the distributor cap to see whether the spark is getting from there to the coil and on to the spark plugs.
Don't forget ! If your P0421 engine code not resolved on and there are trouble codes in your computer, your vehicle will not pass an OBD 2 emissions test. The light must be off and there must be no codes in memory to pass an OBD 2 emissions test. In addition, all of the OBD II self-monitors that check for faults must have run and completed without finding any further problems to pass the test.