P0588 Code: Cruise Control Vent Control Circuit High

What the P0588 code means

The cruise control vent solenoid lets air into the servo so it releases the throttle. For safety, any fault in it disables cruise control.

The computer watches the control circuit from its own driver transistor. The P0588 code means high voltage in the control circuit (an open circuit or a short to voltage). Before you replace the part, check the fuse, relay, connector and wiring, which are the most usual cause.

If the vent does not work, cruise control does not engage or is slow to release the throttle when you brake. For safety, it is best to repair this before you use cruise control again.

To confirm it, measure the continuity of each wire between the component connector and the computer connector with the key off. It should be less than 1 ohm. An infinite reading means the wire is open. If the wiring is good, measure the component itself: infinite resistance confirms it is open inside.

P0588 code symptoms

• Check engine light or another warning light on.
• Cruise control that does not work or does not release.
• Cruise control that does not engage.

Likely causes of the P0588 code

1. Loose or broken connector. The most common cause, especially after another repair.
2. Open coil or motor with infinite resistance.
3. Cut control wire between the component and the computer.
4. Short to 12 V. The control wire touches another wire that carries voltage.

How to diagnose the P0588 code step by step

1. Activate the component with the scan tool and check whether it responds.
2. Check the fuse and relay. Measure voltage on both sides of the fuse and swap the relay with an identical one.
3. Measure the supply at the connector. You should see battery voltage with the key on or when you command it.
4. Measure the component resistance and compare it with the manual, and also check the insulation to ground.
5. Check the control wire for continuity to the computer and for the absence of shorts.

How to fix the P0588 code

• Repair the connector, the wiring or the power supply.
• Replace the cruise control vent solenoid if it does not respond with correct power and command.
• Clear the codes and verify.

Technical reference data

• 12 V solenoid.
• Reference values only: check the manufacturer data for your vehicle.

Brand-specific notes

This is typical of vacuum cruise control systems.

Frequently asked questions about P0588