What Does It Mean?
This is a generic diagnostic trouble code (DTC) for the powertrain and generally applies to OBD-II vehicles. Vehicle makes may include, but are not limited to, Dodge, Chrysler, Jeep, Chevy, Hyundai, Ram, Ford, etc.
There are many possible ways for your vehicle to control your cruise control. One method manufacturers tend to use for controlling cruise control is a vacuum-controlled and actuated system.
Most of the time, they use vacuum as an effective means to control a cruise control servo or a similar diaphragm-type control. The vacuum control circuit is an integral part of the proper functioning of this system. The ECM (Engine Control Module) monitors/adjusts the control side of the vacuum accordingly, based on the operator’s cruise control demands. If the ECM loses its monitoring capabilities for the cruise control vacuum control circuit, it is very likely that your cruise control will stop functioning as it should. Often, these systems will include a vacuum solenoid, which is responsible for controlling the vacuum flow to the control side of the system (i.e., it controls the vehicle’s speed when cruise control is active); that said, in other systems, the vacuum responsibilities are consolidated solely within the cruise control servo. As with many faults, this could be strictly an electrical issue caused by a mechanical problem, vice versa, or both.
While monitoring the sensors, circuits, switches, etc., of your cruise control, not to mention all the other systems in your vehicle, the ECM has detected a fault in the cruise control vacuum control circuit. Most likely, one or more of the monitored electrical values are out of range (i.e., beyond the manufacturer’s desired values).
For P0584, it indicates a high voltage situation within the cruise control electrical vacuum circuit.
How Severe Is This DTC?
To be honest, this fault should not be very concerning from a safety perspective. That said, the severity is set to low to medium. Any issue in a vacuum system, which is often supplied/recycled by the engine, should be resolved sooner rather than later, given some of the possible consequences of neglecting to repair a vacuum system.
I would say that if you have specifically determined that the engine is not affected by this fault, typically in vacuum systems not powered by the intake, and you can live without cruise control, you should be able to postpone addressing this fault if your budget is limited or other things have a higher priority.
What Are Some of the Symptoms of the Code?
Symptoms of a P0584 diagnostic trouble code may include:
Inoperative cruise control
CEL (Check Engine Light) illuminated
Certain functions not working as they should (e.g., set, resume, accelerate, etc.)
Irregular vehicle speed, even with cruise control set to a specific speed
Cruise control light constantly illuminated in the instrument cluster
One or more cruise control functions not operating correctly
Hissing sounds from the engine compartment
What Are Some of the Common Causes of the Code?
Causes
of this P0584 cruise control code may include:
Faulty vacuum solenoid
Faulty cruise control servo
Broken/cracked/disconnected/pinched vacuum lines
Mechanical obstruction in the cruise control servo’s operating range
Wiring issue (e.g., short, open, corrosion, resistance, chafing, etc.)
ECM (Engine Control Module) problem
Mechanical obstruction in the vacuum passages
Seized cruise control servo cable
Engine vacuum system leak
Connector issue (e.g., broken tabs, corroded pins, melted housings, missing insulation, etc.)
What Are the Diagnostic and Troubleshooting Steps for P0584?
The first step in the troubleshooting process for any malfunction is to check the Technical Service Bulletins (TSBs) for known issues with the specific vehicle.
Advanced diagnostic steps become very vehicle-specific and may require the appropriate advanced equipment and knowledge to perform accurately. We include the basic steps below but refer to a repair guide specific to the year/make/model/powertrain for steps tailored to your vehicle.
Basic Step #1
First things first, open the hood to inspect components in your cruise control system. You’ll want to trace the vacuum control line to see where it goes and what it controls. If it goes directly to a vacuum solenoid, carefully inspect the vacuum lines, solenoids, and cruise control servo for physical damage. Anything obvious should be repaired/replaced before continuing diagnostics.
NOTE: When inspecting the cruise control servo, also check that the cable is not seized, as this can cause the monitored electrical value to be exceeded.
Basic Step #2
If a cruise control vacuum solenoid is present, it would be wise to check its electrical values to rule out the possibility of an internal fault. Refer to your vehicle’s service manual for precise values and procedures. I’ve seen them mounted on the firewall, fender wells, intake manifolds, etc., so make sure you are working with the correct solenoid before doing anything. If the recorded values are outside the manufacturer’s desired range, replace the solenoid, clear the engine light, and test the system.
Basic Step #3
If you have used a vacuum gauge at some point, it would be a good idea to monitor the vacuum in the system. It is extremely important to acquire vacuum from specific orifices in the intake systems. Generally, they will be located on the intake manifold itself, but refer to your manual for details. This depends heavily on your engine’s specifics, but normally, at operating temperature with correct ignition timing, the vacuum reading should be around 50 to 55 kPa.