P0584 code definition
The P0584 trouble code notes an error with the cruise control vacuum control circuit.
What the P0584 code means
The P0584 code is a standard OBD-II trouble code that signals an electrical issue with the cruise control vacuum control circuit. The cruise control system, which allows the vehicle to maintain a constant speed, is controlled by the powertrain control module (PCM) and cruise control module, which work together to control the speed. When the vehicle is unable to control the speed, the PCM will test the cruise control system in totality, and if a vacuum control circuit error is detected, the P0584 code will be issued.
What causes the P0584 code?
The most common causes of the P0584 trouble code are:
- Defective vacuum supply hose leading to the cruise control servo
- Defective one-way in line check valve leading to the cruise control servo
- Damaged electrical components in the system (such as wires, connectors, and fuses)
- Malfunctioning cruise control switch
What are the symptoms of the P0584 code?
The P0584 trouble code will often be accompanied by the check engine soon Warning Light, which will illuminate in the gauge cluster. In most cases, the cruise control system will not work at all.
How does a mechanic diagnose the P0584 code?
The P0584 code will be diagnosed with the help of an OBD-II trouble code scanner. A trained mechanic can use the scanner to observe the freeze frame data, which will offer information about the code. At this time the mechanic will also check to see if there are any additional trouble codes stored, as codes should always be addressed in the order in which the scanner displays them. The trouble codes will then be reset, and the vehicle will be restarted, to see if the code returns. If the code does not return, then it should be assumed that was erroneously detected, or that there is an intermittent error.
If the code remains detected following the reset, then the mechanic will visually inspect the electrical components in the cruise control system. Any damaged circuits, shorted wires, blown fuses, or loose or corroded connectors should be replaced.
Next, the vacuum supply hoses in the system will need to be inspected. If a visual inspection yields no results, then a vacuum pressure test can be done, with the results compared to those of the manufacturer’s specifications. The one-way valve can then be tested by blowing through it in both directions. If it can be blown through in both directions, then it is defective and requires replacement. If the issue is still unsolved, then a defective cruise control switch is likely the culprit.
After any and all replacements, the mechanic will need to stop and reset the trouble codes, restart the vehicle, and check again for the code. By doing this, the technician will know as soon as the issue is resolved.
Common mistakes when diagnosing the P0584 code
The most frequently made mistake when diagnosing this code comes from a failure to properly follow the OBD-II trouble code diagnosis protocol. It’s imperative that technicians abide by the protocol at all times, as this results in an effective and efficient diagnosis.
Erroneous repairs are commonly made when an electrical issue was the only problem in the system.
How serious is the P0584 code?
A vehicle with a detected P0584 trouble code will still be drivable, though the cruise control system will most likely be inoperable.
What repairs can fix the P0584 code?
Common repairs for the P0584 trouble code are:
- Replacement of the vacuum supply hose
- Replacement of the one-way valve
- Replacement of wires, connectors, fuses, and circuits
- Replacement of the cruise control switch
Additional comments for consideration regarding the P0584 code
The P0584 trouble code only applies to vehicles with cruise control systems. In some vehicles, the error will have to be noted by the PCM multiple times before the check engine soon Warning Light will be illuminated.
Need help with a P0584 code?
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