Error Code P0588 is defined as is defined as Cruise Control Vent Control Circuit High. It’s a problem in the cruise control vent control circuit, likely caused by defective vent control solenoid or damaged cruise control circuitry.

This code is a generic trouble code, meaning it applies to all vehicles equipped with the OBD-II system and cruise control system. It is particularly prevalent among Chevrolet, Chrysler, Dodge, Hyundai, Honda, Ram, etc. Specifications on the definition, troubleshooting, and repairs vary from one make and model, and powertrain configuration.

Cruise control makes driving a more pleasurable and safe experience. While its primary function is to control speed, it has other uses too:

It will allow the vehicle to accelerate or decelerate by 1 mile per hour (for example) with a simple tap of a button it will keep you and your passengers safe by disengaging as soon as you step on the brake pedal. Also, it will not activate under 25 mph.

The Cruise Control system is controlled by the PCM (powertrain control module, also known as ECM or engine control module in other vehicle makes), or by a Cruise Control Module in other makes. The PCM has a vast amount of readings to control the speed of the vehicle automatically. If drivers can’t control the vehicle’s speed with cruise, the PCM will run a test that includes the whole cruise control system to identify potential problems.

In most cases, the Cruise Control Vent is used to control the said system and ensure the PCM can adjust the vacuum within the system. The function of the vent is essential, as it can affect the cruise control servo’s function. The servo is responsible for adjusting and controlling the speed when the cruise control is activated.

If the self-diagnose test of the PCM reveals a problem, it will activate a cruise control code based on the problem.

Error Code P0588 is a generic trouble code that appears when the self-diagnose test of PCM shows electrical level from the cruise control vent circuit that is HIGHER than normal.

Common Symptoms

Check Engine light will be activated on the dashboard, and the code will be registered. Other common symptoms for the code include:

  • If the code is set in the PCM, vehicle control speed will not be set using the cruise control
  • Blown fuse
  • One or more control function not working
  • Intermittent/irregular general cruise control functionality

Possible Causes

The most common cause for this code is damaged electrical components in the cruise control system. Also, the switch can malfunction from liquid spills in the vehicle’s interior. Other possible causes include:

  • Bad electrical connection in speed control/vent control solenoid
  • An open or short circuit in speed control/vent control harness
  • Obstruction within cruise control system
  • Vacuum leak in cruise control system
  • Corroded or damaged connectors
  • Damaged vent control solenoid
  • Blown fuse (can be a sign of a more serious underlying cruise control vent control circuit)

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.

First Step

The most common repair for this code is simply replacing the cruise control switch. However, before proceeding with any replacements, make sure you conduct a thorough diagnosis to pinpoint the exact cause of the problem. You can follow the diagnostic steps from the vehicle’s service manual to determine whether a faulty switch is causing the problem.

Start by disconnecting the vehicle’s battery. Then, using a screwdriver, remove the steering wheel column bolt covers. Remove ratchet if necessary as well.

You may need to remove the center airbag cluster from the center of the steering wheel. Unbolt it from the back of the steering wheel.

Next, disconnect the electrical connector to the airbag cluster by pressing its side clips and pulling them from the hard plastic side areas. You may have to remove the steering wheel to get access to the switch. You may need a special puller for this.

Note: Make sure you refer to your vehicle’s service manual for the proper steering wheel or airbag removal procedures.

Once you have disconnected the electrical connectors from the cruise control switch, detach the switch by removing the bolts that hold the switch onto the steering column bracket. Then, replace the old cruise control switch with a new one and reinstall everything.

Reconnect the battery and then take the vehicle for a test drive. Of course, make sure the traffic isn’t too bad so you can use the cruise control and be safe.

Second Step

Another common cause for this code is a mechanical problem within the cruise control vacuum system. This could be physical damage to the cruise control vacuum solenoid itself, and a vacuum leak in the system, which may be caused by obstructed lines, kinked, etc. These mechanical problems are easy to spot when inspecting the components involved in the system.

Vacuum leaks must be repaired, if not replaced. Again, refer to your vehicle’s service manual for the specific diagnosis and repair procedure.

How to Fix

Common repairs for this code include:

  • Replacement of vent control solenoid
  • Replacement of damaged connectors, fuses, and wires in the cruise control system
  • Replacement of circuitry
  • Replacement of leaking vacuum hoses and valves

This error code doesn’t impose serious driving safety concern. However, if you rely on the cruise control system on a regular basis, then it must be addressed as soon as possible and keep it from getting worse.

It’s common to overlook blown fuses when diagnosing this code, so make sure you check it as well.