P0589 OBD-II Trouble Code: Cruise Control Multi-Function Input “B” Circuit**

check engine light

P0589 Code Definition

The P0589 code is a generic powertrain code related to the vehicle speed control and idle control system. In this case, the engine control module (ECM) has found a fault in the cruise control multi-function input “B” circuit.

Codes related to the P0589 include: * P0590: Cruise Control Multi-Function Input “B” Circuit Stuck * P0591: Cruise Control Multi-Function Input “B” Circuit Range/Performance * P0592: Cruise Control Multi-Function Input “B” Circuit Low * P0593: Cruise Control Multi-Function Input “B” Circuit High

What the P0589 Code Means

When a P0589 code is stored, the vehicle’s ECM has found a fault in the electrical circuit of the cruise control system. A vehicle’s ECM works with the cruise control module (on most vehicles) to automatically control the vehicle’s speed. Cruise control works to help a driver maintain a safe speed without the need to constantly keep pressure on the accelerator pedal.

In most modern vehicles, cruise control is achieved through the use of a small servo motor attached to the throttle linkage. The ECM and cruise control module sends a voltage signal, telling the servo motor to open the throttle to slow the vehicle, or close the throttle to increase the vehicle’s speed.

A vacuum operated cruise control system uses a combination of vacuum from the engine and the electronic cruise control module to operate. Engine vacuum is constantly supplied to the cruise control servo solenoid, and when the cruise control module sends the signal to set the cruise control, the servo solenoid opens for vacuum to get to the servo. Then, the cruise control module utilizes a signal from the cruise control switch operated by the driver to ensure the correct amount of vacuum to decrease, maintain, or increase engine speed as necessary.

This P0589 code can be caused by the variable valve or cylinder management system turning on and off during cruising speeds, light throttle conditions, or on flatter roads. This excessive switching can cause increased oil consumption, dropping oil pressure levels outside of allowed parameters and can no longer operate the valve or cylinder management system. If the ECM cannot control the vehicle’s speed, the system initiates a self test and stores the P0589 code if the voltage/resistance level in the cruise control system is not normal.

What Causes the P0589 Code?

Several problems may cause a P0589 code including: * Damaged, defective, or faulty cruise control switch * Damaged, open, or shorted circuitry in the cruise control button (possibly caused by spilled liquids) * Damaged or leaking vacuum supply hose * Blown fuse(s) * Damaged or corroded connectors

What are the Symptoms of the P0589 Code?

Symptoms of a P0589 code may include: * Warning or service light may illuminate * Cruise control may not engage * Cruise control may engage and disengage * There may be no obvious symptoms aside from a stored code

How Does a Mechanic Diagnose the P0589 Code?

A mechanic may use several methods to diagnose a P0589 trouble code, including: * Utilize an OBD-II scanner to check for a stored P0589 trouble code * Check for blown fuse(s) * Visually inspect wiring and connectors for signs of damage or corrosion * Visually inspect the vacuum supply hoses for damage * Perform a vacuum pressure test * Test the one-way vacuum valve (blow air through both ends to ensure air only goes through one direction) * Test the cruise control switch for voltage with a digital volt/ohmmeter * Test continuity in the cruise control circuitry

Common Mistakes when Diagnosing the P0589 Code

If a fuse is blown, be aware that it may be a symptom of a larger problem. Be sure to check for all stored diagnostic trouble codes (DTCs) and diagnose them in the order in which they appear.

How Serious is the P0589 Code?

Because a vehicle’s safe driving operation will most likely not be impacted due to faults that store a P0589 code, this code is not considered to be serious code. However, when this code appears, it is recommended to take your vehicle to your local service center or mechanic for repair and diagnosis as soon as possible.

What Repairs can Fix the P0589 Code?

Several repairs can fix a P0589 trouble code and include: * Repair or replace any damaged, corroded, or loose wiring or connectors * Replace any blown fuse(s) * Replace any damaged connectors * Replace any damaged vacuum supply hoses * Replace damaged or defective one-way vacuum valve * Replace a damaged or defective cruise control switch * Clear all codes, test-drive the vehicle, and rescan to see if any codes reappear

Additional Comments for Consideration Regarding the P0589 Code

Sometimes, a P0589 code can be caused simply from spilling liquids inside your vehicle. Keep your vehicle clean and in good operating condition, and avoid expensive repairs that can be avoided.

Need Help with a P0589 Code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

More related articles

The Traveler’s Guide to Driving in Malaysia
CraigBurrows / Shutterstock.com Malaysia is a popular destination for many tourists today. The country has amazing sights and attractions that you will want to explore....
P2422 OBD-II Trouble Code: Evaporative Emissions Control System (EVAP) Vent Valve Stuck Closed
Diagnostic Trouble Code (DTC): P2422 P2422 code definition Evaporative Emissions Control System (EVAP) Vent Valve Stuck Closed Related Trouble Codes: P2441: EVAP Vent Valve Stuck Open EVAP trouble...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...

Related questions

Q: AT light and Check engine light on stuck in third gear.

A logical place to start is with a Check Engine Light inspection to see what codes might be set. Usually with something of this nature, codes will be present, and there will be a flow chart that should be used...

Q: EGR warning

Hello. An EGR valve that is intermittently failing will cause the Check Engine Light to turn off and on. If the code is for the EGR valve and the voltages to the valve are correct, then the EGR valve may...

Q: I need help with diagnostic trouble codes that suddenly appeared making vehicle almost undriveable.

Firstly, you should have the battery disconnected and the PCM disconnected. Check their connectors for any problems and apply dielectric lube to the connectors so the connection is clean from corrosion. If the problem continues then replace the PCM. All...