Technical Description of OBD-II Trouble Code
The circuit responsible for controlling the vacuum in the cruise control system is operating at a high level.
What does that mean?
This is a standard diagnostic trouble code (DTC) that applies to OBD-II vehicles. It can be found in various vehicle makes such as Dodge, Chrysler, Jeep, Chevy, Hyundai, Ram, Ford, etc.
Manufacturers often use a vacuum-controlled system to regulate the cruise control. The vacuum control circuit is essential for the proper functioning of this system. The ECM (Engine control module) monitors and adjusts the vacuum control side based on the driver’s cruise control demands. If the ECM loses its ability to monitor the cruise control vacuum control circuit, the cruise control may stop working correctly. In some systems, a vacuum solenoid is responsible for controlling the vacuum flow, while in others, the cruise control servo handles this task. This fault could be caused by an electrical issue, a mechanical issue, or a combination of both.
The ECM has detected a fault in the cruise control vacuum control circuit while monitoring various sensors, circuits, switches, and other systems in the vehicle. This fault is indicated by the P0584 code, which signifies a high voltage situation in the cruise control vacuum electrical circuit.
What is the severity of this DTC?
In terms of safety, this fault is not a major concern. However, it is recommended to address any issues within the vacuum system, as neglecting them could lead to potential consequences. The severity of this DTC is considered low-medium. If the engine is not affected by this fault and you can manage without cruise control, you can delay fixing it if you have budget constraints or other higher priority tasks.
What are some of the symptoms of the code?
Some symptoms associated with the P0584 diagnostic code include:
What are some of the common causes of the code?
The causes of the P0584 cruise control code may include:
What are some P0584 diagnostic and troubleshooting steps?
The first step in troubleshooting any malfunction is to consult the Technical Service Bulletins (TSB) for known issues with the specific vehicle.
Advanced diagnostic steps are highly specific to the vehicle and may require specialized equipment and knowledge. The following are basic steps, but it is recommended to refer to a vehicle-specific repair guide for precise steps.
Basic Step #1
Inspect the cruise control system under the hood. Trace the vacuum control line to determine its path and what it controls. If it connects to a vacuum solenoid, thoroughly examine the vacuum lines, solenoids, and cruise control servo for any physical damage. Repair or replace any obvious issues before further diagnosis.
NOTE: When inspecting the cruise control servo, ensure that the cable is not seized, as this can affect the monitored electrical values.
Basic Step #2
If a cruise control vacuum solenoid is present, check its electrical values to rule out any internal faults. Refer to the vehicle’s service manual for precise values and procedures. Depending on the vehicle, the solenoid may be mounted on the firewall, fender wells, intake manifolds, etc. If the recorded values are outside the manufacturer’s desired range, replace the solenoid, clear the engine light, and test drive the system.
Basic Step #3
If you have access to a vacuum gauge, monitor the vacuum within the system. It is crucial to measure the vacuum from specific ports on the intake systems. Typically, these ports are located on the intake manifold, but refer to the manual for specific instructions. The vacuum reading should be around 50-55 kPa at operating temperature, with correct ignition timing.
