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Error Code P0582 is defined as Cruise Control Vacuum Control Circuit/Open. This code is a generic trouble code, meaning it applies to all vehicles equipped with the OBD-II system, particularly vehicles made since 1996 up to present. It is particularly common but not limited to Chrysler, Chevrolet, Dodge, Ford, Hyundai, Ram, etc. Specifications on the definition, troubleshooting, and repairs vary from one powertrain model type, and make and model to another.
There are many ways the vehicle goes about in controlling the cruise control system. One of the things manufacturers use is through vacuum control and the operating system.
They use the vacuum as an efficient way of controlling a cruise control servo, or similar diaphragm-type control. The vacuum control circuit plays an important role in the proper operation of the system. The PCM (powertrain control module, also known as ECM or engine control module in other vehicle makes) monitors and adjusts the vacuum control side accordingly, depending on the demands of the operator’s cruise control.
If the PCM loses its monitoring capabilities to the cruise control vacuum control circuit, it will cause the cruise control system to malfunction. Many times, this system includes a vacuum solenoid, which oversees the vacuum flow to the control side of the system (i.e., controls the speed of the vehicle when the cruise is active). With this, in other systems, the responsibilities of the vacuum are consolidated to solely to the cruise control servo. As with most faults, this code could be an electrical problem caused by a mechanical issue, vice versa, or both.
While monitoring cruise control circuits, sensors, switches, etc., not to mention other systems in the vehicle, the PCM has detected the fault within the cruise control vacuum control circuit. In this case, one or more electrical values being monitored has gone out of range (i.e., beyond specifications set by the manufacturer).
Error Code P0582 is a general fault within the circuit or could mean a loss of continuity in the cruise control vacuum electrical circuit.
As with other error codes, this code activates the Check Engine light and registers the code to the vehicle’s memory system. Other common symptoms include:
- Inoperative cruise control
- Other functions of cruise control not functioning (accel., set, resume, etc.)
- One or more cruise control functions not working properly
- Erratic vehicle speed, even when cruise control is set to a specific speed
- Cruise control light permanently in the instrument cluster
- Whistling noises coming from the engine bay
Multiple factors contribute to this code, such as:
- Defective vacuum solenoid
- Defective cruise control servo
- Broken, cracked, disconnected, or kinked vacuum lines
- Wiring problems (corrosion, open, short, chafed, etc.)
- Connector problems (corroded pins, broken tabs, missing insulations, melted housing, e tc.)
- Mechanical obstruction in the cruise control servo’s operating range
- Mechanical obstruction in the vacuum passageways
- Seized cruise control servo cable
- Leaks in the engine vacuum system
- PCM issue (rare)
How to Check
The best start for diagnosis of this code is to check the TSB (Technical Service Bulletin) for known issues with the specific vehicle. Some vehicles may require advanced diagnostic steps and special tools, which differs from one type of vehicle to another. Here are some basic steps for diagnosis.
The first thing must be checked is the cruise control system. Trace back the vacuum control line to see where it leads and what it controls. If it goes straight to the vacuum solenoid, check the solenoids, vacuum lines, and cruise control servo thoroughly, look for any signs of damage. Any damaged components must be repaired/replaced before going forward with the diagnosis.
When checking the cruise control servo, make sure the cable is not seized, as this can cause the monitored electrical values to be erratic.
If the cruise control vacuum solenoid is present, rule out the possibility of an internal fault by verifying the electrical values. Again, refer to your vehicle’s service manual for the exact values and procedures. In some cases, they can be mounted to the fender wells, firewall, intake manifold, etc., so make sure you’re working with the right solenoid before doing anything.
If you get values outside the specified range allowed by the manufacturer, then the solenoid must be replaced. Clear the engine light and then test drive the system.
If you have used a vacuum gauge beforehand, then it’s a good idea to monitor the vacuum within the system. It’s important to get the vacuum from specific ports off the intake systems. Generally, these are located on the intake manifold itself, but again, make sure you refer to your service manual to be sure. This depends on the specifics of the engine, but generally, at the operating temperature, with the right ignition timing, the vacuum reading must be 50 to 55kPa.
How to Fix
Depending on the diagnosis, common repairs for the code include:
- Replacement of cracked or damaged vacuum lines
- Replacement of blown fuses
- Replacement of failed cruise control vacuum solenoid
- Replacement of failed one-way check valve
The most common mistake in dealing with this code is replacing the cruise control vacuum solenoid when the problem is actually in the one-way check valve. A blown fuse is a common hidden cause as well, though it generally highlights other more serious problem.