OBD-II Code P0592 — What It Means & How to Fix It

What Does This Error Mean?

P0592 means the cruise control multi-function switch circuit voltage is too low. Your PCM expects to see a voltage in a specific range from the cruise control switch. When the voltage drops below the minimum — and stays there — this code is triggered. A short to ground in the wiring, a stuck switch, or a failed switch are the most common causes. Cruise control will not work while this code is active.

Affected Models

All vehicles 1996+
Common in GM vehicles 2000-2015
Common in Dodge and Chrysler vehicles
Common in Ford trucks and vans
Common in any vehicle where cruise control switch shares a ground reference circuit

Common Causes

A short to ground in the switch signal wire — the most common electrical cause
A cruise control switch button that is stuck in the pressed position
Failed switch with an internal short that pulls the circuit low
Pinched wiring harness shorting against the vehicle body or chassis
Corroded connector creating a low-resistance path to ground

How to Fix It

With the key on and engine off, use a scan tool to observe the live cruise control switch voltage. A P0592 will typically show a voltage reading near zero volts or below the expected minimum.

The normal voltage with no buttons pressed varies by manufacturer — check your vehicle's service data for the exact specification.
Physically inspect the cruise control switch buttons. Press each one and see if any feel stuck or do not return to the neutral position. A stuck 'Set' or 'Cancel' button can pull the circuit voltage low.

On high-mileage vehicles, sticky residue or debris under the switch buttons is a surprisingly common cause.
Unplug the cruise control switch connector and recheck the circuit voltage at the harness side. If the voltage returns to normal after unplugging, the switch itself is faulty and needs replacement.

If the voltage stays low even after unplugging the switch, the problem is in the wiring — there is a short to ground somewhere in the harness.
Inspect the wiring harness from the switch back to the PCM. Look for any areas where the insulation has worn through against metal edges, especially around the steering column and firewall.

Pay attention to areas where the harness is routed around heat sources or moving parts.
Replace the switch if it tested as faulty, or repair the shorted wire if found. Clear the code and test all cruise control functions before returning the vehicle to service.

After clearing, the code should not return as long as all cruise control buttons are released and working normally.

When to Call a Professional

If you cannot locate a short to ground yourself, a shop with a wiring diagram and a digital multimeter can trace the fault quickly. Electrical diagnosis rates typically run $75 to $150 per hour. The total repair cost depends on whether the fault is in the switch ($30 to $180) or in the wiring harness.

Frequently Asked Questions

What is the difference between P0592 (low) and P0593 (high)?

P0592 means the circuit voltage is too low — usually pointing to a short to ground or a stuck button pulling the voltage down. P0593 means the voltage is too high — usually pointing to an open circuit or a short to power. Both codes disable cruise control.

Can rain or car washing cause P0592?

Yes, water can get into the switch housing or connector and create a short to ground. If P0592 appears after wet weather or washing and then clears on its own after drying out, check the switch and connector for moisture sealing.

Will P0592 affect my regular driving?

No — your engine, brakes, steering, and transmission are all unaffected. Only cruise control is disabled. You can drive the car normally until you get it repaired.