OBD-II trouble code
P0583: Cruise Control Vacuum Control Circuit Low
Because the module switches this solenoid on its ground side, low is the energised state. A circuit stuck low is a solenoid that is on when nobody asked for it — which is why this one is worth attending to promptly.
Quick facts
- System
- Powertrain
- Category
- Cruise Control
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $80 – $650
- DIY difficulty
- Intermediate DIY
What does P0583 mean?
P0583 sets when the module sees the vacuum solenoid control line at a low voltage when it should not be. Getting value out of that sentence requires knowing how the circuit is wired, because the intuitive reading of low is wrong here.
These solenoids are almost universally switched on the ground side. The solenoid gets its supply from a fuse or a relay, and the module contains a transistor that connects the other end of the coil to ground when it wants the solenoid to operate. So when the module commands the solenoid on, the control line is meant to be low. Low is not the fault condition in itself — low at the wrong moment is. The module has found the line pulled down while it had the driver switched off, and what it is reporting is that something other than itself is energising the solenoid.
That gives this code a consequence none of its siblings share. An energised vacuum solenoid admits manifold vacuum to the servo diaphragm continuously, and on a mechanical-throttle vehicle the servo's job is to pull the throttle open. A solenoid held on by a short to ground is therefore a servo applying throttle without being asked. In practice this rarely results in anything dramatic, because the systems were designed on the assumption that this exact failure could occur. The vent solenoid is arranged so that losing power dumps the vacuum, the brake pedal switch releases the servo mechanically as well as electrically on essentially every such design, and the throttle return spring is stronger than a partially applied servo. But the failure direction is toward action rather than inaction, and that alone is why this code sits above the rest of the block in severity and should not be left for months.
The cause list is dominated by one thing, and its physical explanation is specific to where the part lives. The servo is a metal canister bolted to the bulkhead or inner wing, which makes it a large, well-grounded object with the solenoid's own harness draped across it. A wire whose insulation has worn through against the servo's mounting flange, a bracket edge or a fastener does not have to travel anywhere to find ground — it is already touching it. That is why the fault on this circuit is so often found within a few inches of the solenoid rather than somewhere out in the loom, and why the inspection should start at the component and work outward instead of the other way round.
There is one technique here that is more useful than any single measurement. Unplug the solenoid and see what the module complains about next. If the stored fault becomes the open-circuit code, the unwanted ground was on the solenoid side of that connector. If the line stays low with nothing connected at all, the short is upstream in the harness. You have deliberately caused a different fault in order to find out which half of the circuit you are working in, and it takes about a minute.
Common causes
- Control wire shorted to ground against the servo mounting flange or bracket
- Chafed insulation where the solenoid harness crosses the metal servo body
- Internally shorted vacuum solenoid winding contacting the solenoid case
- Water intrusion into the solenoid connector creating a path to ground
- Pinched or crushed harness from previous engine bay work
- Corrosion inside the connector bridging the control terminal to a ground terminal
- Incorrectly repaired splice joining the control wire to a ground circuit
- Failed module output driver stuck in the conducting state, which is genuine but uncommon
Symptoms
- Cruise control unavailable or refusing to engage
- Throttle linkage under tension with the ignition on and cruise switched off
- Slightly elevated or unstable idle on a mechanical-throttle vehicle
- Cruise control engaging on its own or holding speed after being cancelled
- Cruise control feeling aggressive or overshooting the set speed
- Check engine light with no misfire and no other engine complaint
- Fault appearing shortly after work was done near the servo or bulkhead
- Behaviour worsening in wet weather where water intrusion is the cause
Diagnostic steps
- 1.Understand which side of the solenoid the module controls before interpreting the word low. On almost every design of this era the solenoid receives a battery or ignition-switched feed and the module completes the circuit to ground when it wants the solenoid energised. Low is therefore the switched-on state, and this code means the module found the line pulled down at a time when it had commanded the solenoid off. You are not looking for missing voltage — you are looking for an unwanted path to ground.
- 2.Unplug the solenoid connector and see what the module reports next. This is the most efficient step available on this circuit. If the stored fault changes to the open-circuit code, the unwanted ground was inside the solenoid or on the solenoid side of that connector. If the low condition persists with nothing plugged in, the short is in the harness between the module and the connector you just opened. You have deliberately provoked the other fault in order to learn which half of the circuit you are in.
- 3.Measure from the control wire to a known good ground with the solenoid disconnected and the module connector also disconnected. Anything other than an effectively open reading is your fault, and it does not need to be a dead short. Enough leakage to be measured is enough to hold a driver circuit low.
- 4.Trace the control wire's route with the servo body specifically in mind. The servo canister is metal and bolted to the bulkhead, which makes it a large grounded object with the solenoid harness running across it. A conductor chafed against the servo's own mounting flange or bracket finds ground immediately and without travelling anywhere, which is why the fault is often within a few inches of the part rather than out in the loom.
- 5.Confirm whether the solenoid is being energised continuously by feeling and listening at the servo with the ignition on and cruise control switched off, then by watching the throttle linkage. A solenoid held on admits manifold vacuum continuously, and on a mechanical-throttle vehicle that means the servo is trying to pull the throttle open while nobody has asked it to. If you can see the linkage under tension, you have confirmed the fault physically as well as electrically.
- 6.Test the module's driver only after the wiring has been cleared. With the harness proved good and the solenoid proved good, a line held low points to an output driver that has failed conducting. That is a real failure mode, but it is the last conclusion rather than the first, and it should never be reached without having ruled out the short to ground that causes the same symptom for a fraction of the price.
Repair cost
$80 – $650
The most likely repair is also the cheapest: finding and correcting a shorted or chafed control wire is $60 to $200 of labour with a few dollars of materials, and locating it near the servo means the access is usually good. Diagnosis runs $90 to $170 since it needs an insulation resistance measurement and the disconnect-and-observe step rather than a single reading. An internally shorted solenoid available as a separate part is $30 to $150 plus half an hour to an hour. Where the solenoid is integral, a complete servo is $120 to $600 plus one to three hours including cable adjustment. A failed module driver is the expensive tail of the range and is uncommon enough that it should never be assumed without the wiring having been cleared first.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with cruise control servo / actuator replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.