What it means
Same as P0586 with the control line shorted to supply. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
At a glance
- Usually lights the check-engine light
How it works
On a vacuum-operated cruise system, the vent solenoid releases vacuum from the throttle servo when cruise speed is reduced or canceled. P0588 sets when the vent-control circuit is higher than expected, typically because its control wire is shorted to a supply.
Common causes
Most likely first.
- Control line shorted to supply
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Cruise control unavailable or disengages
- Cruise-control buttons may not respond
- Check-engine light
How to diagnose it
- Review freeze-frame and related cruise codes, and confirm the vehicle uses a vacuum-operated cruise servo.
- Inspect the vent-solenoid connector and harness for pinched insulation, water entry, pushed-back pins, or contact with a power source.
- Compare the module's vent command with circuit status in scan-tool data, if available, when requesting cruise cancel or speed reduction.
- With the circuit isolated according to the wiring diagram, test the vent-control wire for a short to a supply circuit.
- If the wiring is sound, test the vent solenoid and module output using the manufacturer's procedure.
Common fixes
- Reroute and secure wiring pinched against a power source.
- Repair the vent-control wire shorted to supply.
- Clean or replace damaged vent-solenoid connector terminals.
- Replace the vent solenoid if it fails the manufacturer's test.
- Repair or replace the module only after the external circuit passes testing.
Can I keep driving?
Avoid cruise control until the vent circuit is repaired because the vent solenoid helps release vacuum from the throttle servo. If cruise does not cancel normally, use the brake or cancel control and stop safely.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.