Medium Severity — Powertrain OBD-II DTC

P0689: Computer and Auxiliary Outputs Malfunction (P0689)

P0689 is a generic (SAE standard) powertrain diagnostic trouble code (DTC) indicating: Computer and Auxiliary Outputs Malfunction (P0689). This code is set when the vehicle's onboard computer (ECM/PCM) detects a fault in the computer and auxiliary outputs system.

⚡ Quick Summary

Severity

Medium

DIY Level

Moderate

Repair Cost

$80–$300

Urgency

Fix within weeks

🚨 Symptoms of P0689

▸ Check engine light on

▸ Various drivability issues depending on the affected output

▸ Component not functioning (fan, relay, solenoid)

🔍 Common Causes of P0689

HIGH

Faulty computer and auxiliary outputs component

MED

Wiring issue — open, short, or corroded connector

LOW

ECM/PCM software issue or internal failure

🛠️ How to Fix P0689

⭐ Most Common Fix

Diagnose and repair computer and auxiliary outputs circuit

💰 $80–$300 🔧 Moderate

Repair or replace damaged wiring/connectors

💰 $50–$200 🔧 Easy

Replace faulty computer and auxiliary outputs component

💰 $150–$500 🔧 Moderate

🔬 Step-by-Step Diagnosis

1 Check the affected output circuit with a test light or multimeter
2 Verify power and ground at the component connector
3 Test the ECU output pin with a noid light or oscilloscope
4 Check for short circuits in the wiring harness

⚠️ Common Mistakes to Avoid

✗ Replacing the ECU/PCM without testing the output circuit first
✗ Not checking for corroded connectors or ground points

💡 Pro Tips

★ Always check for Technical Service Bulletins (TSBs) for your specific vehicle — manufacturers often release updated repair procedures for common P0689 issues.
★ Before replacing expensive parts, verify power, ground, and signal at the component connector with a multimeter.

❓ Frequently Asked Questions

What does P0689 mean? ▾

P0689 means Computer and Auxiliary Outputs Malfunction (P0689). The vehicle's computer has detected a fault in this system that needs diagnosis.

Can I drive with code P0689? ▾

This is a moderate issue. You can usually drive with this code, but schedule a diagnosis soon to prevent potential problems.

How much does it cost to fix P0689? ▾

Repair costs vary widely depending on the root cause. Diagnosis typically costs $80-$150. Repairs can range from $50 for simple fixes to $500+ for major component replacements. Always get a diagnosis before authorizing repairs.

🏥 When to See a Mechanic

If you're not comfortable with electrical diagnosis or don't have a multimeter and OBD-II scanner, have a qualified mechanic diagnose P0689. This code involves the computer and auxiliary outputs system which may require specialized knowledge.

🚗 Commonly Affected Vehicles

Based on NHTSA complaint data and community reports. P0689 has been reported in the following vehicles:

🚙

2018 CHEVROLET MALIBU

Sources: NHTSA complaints database, automotive community forums. This is not an exhaustive list — P0689 can occur in any vehicle with an OBD-II system.

Browse Codes by System

Misfires O2 Sensors Catalytic Converter EVAP System VVT/Camshaft Fuel System Cooling System Throttle Knock Sensor EGR System

Disclaimer: This information is for educational purposes only. It is not intended as repair advice and we are not responsible for any actions you take on any vehicle. Always consult a qualified mechanic for diagnosis and repair. Repair costs shown are estimates and may vary by location, vehicle, and shop.