The P0004 fault code applies to all car manufacturers and means the fuel quantity regulator control circuit is high.
Background Information: (In modern cars where fuel injectors are widely used, fuel quantity regulators are rarely used anymore.)
After troubleshooting a car problem, fault codes need to be cleared. When clearing fault codes, it is crucial to follow the specific method specified for your car model. Never directly disconnect the negative ground wire to clear the fault codes. Doing so may cause two problems: First, it may cause the control center computer in some models to lose its normal records. Many car owners know that most car models’ central computer has a memory function. If the negative battery connection is disconnected, the engine operating experience data in the random access memory will be lost, resulting in poor performance for a considerable period after repair, or the cleared fault codes reappearing after a while. Second, it may cause the loss of normal functions. For example, the audio system locking is a common example. In this case, a more complicated procedure is needed to decrypt the audio system to restore its normal operation.
Tip: To quickly find fault codes, you can use a professional OBD2 scanner to obtain the corresponding fault codes, which can help pinpoint the exact problem. This data can help you understand the performance of vehicle components and troubleshoot potential problems before they become serious.