Scag Check Engine Light Codes(Learn and Fix)

In today’s digital age, where technology intertwines with even the most traditional of industries, lawn care and landscaping are no exception.

Scag, a renowned manufacturer of commercial lawn mowers, has incorporated sophisticated engine management systems into its equipment.

While these systems enhance performance, they can also trigger the dreaded “check engine” light.

In this post, we’ll delve into Scag check engine light codes, helping you understand what they mean and how to troubleshoot common issues.

Let’s jump in.

Scag Check Engine Light Codes

Scag Check Engine Light Codes

What Are Scag Check Engine Light Codes?

The mower’s engine management system generates diagnostic signals known as Scag check engine lights.

These codes are designed to indicate specific problems or irregularities within the mower’s operation. They serve as a valuable tool for diagnosing issues promptly.

Read Spartan Mower Electric Fault Code(Crack all Error Codes)

Reasons for Scag Check Engine Codes

1. Identifying sensor failures

One common cause of Scag check engine light codes is sensor failure. Modern mowers are equipped with various sensors that monitor vital engine functions. When a sensor fails or provides inaccurate data, it triggers a code.

2. Fuel System Issues

Issues within the fuel system can also lead to engine codes. Clogged fuel filters, malfunctioning injectors, or problems with the fuel pump can all affect engine performance and trigger warning lights.

3. Ignition Problems

Faulty ignition components, such as spark plugs or the ignition coil, can result in misfires and subsequent check engine codes. Ignition problems can compromise engine efficiency and lead to increased emissions.

Read John Deere SPN Codes(A to Z Codes)

How to Retrieve Scag Check Engine Codes

Retrieving Scag check engine codes is a straightforward process. Most Scag mowers come with a diagnostic port where you can connect a code reader.

These code readers are readily available and provide you with a numerical code that corresponds to a specific issue.

Read How to Change Code on a Spartan Mower(In 3 Quick Ways)

Interpreting Scag Check Engine Light Codes

Interpreting the codes may seem daunting, but they often come with a user manual or can be found online. Understanding these codes allows you to pinpoint the problem quickly.

Scag Check Engine Light CodePossible CausesSolutions
Code P0016Camshaft Position Sensor A – Camshaft and Crankshaft MisalignmentInspect and replace the camshaft position sensor if necessary. Check for timing chain or belt issues.
Code P0171System Too Lean (Bank 1)Check for air leaks in the intake system, inspect the mass airflow sensor, and replace the oxygen sensor if needed.
Code P0172System Too Rich (Bank 1)Inspect and clean the mass airflow sensor. Check for fuel pressure issues and repair as necessary.
Code P0300Random/Multiple Cylinder Misfire DetectedInspect spark plugs, ignition coils, and wires. Check for vacuum leaks and fuel delivery problems.
Code P0420Catalyst System Efficiency Below Threshold (Bank 1)Inspect the catalytic converter for damage and replace if necessary. Check for exhaust leaks.
Code P0505Idle Air Control SystemClean or replace the idle air control valve. Check for vacuum leaks.
Code P0562System Voltage LowInspect the battery and charging system for issues. Replace the battery or alternator if needed.
Code P0700Transmission Control System (MIL Request)Consult a qualified technician to diagnose and repair transmission issues.
Code P1128Closed Loop Fueling Not Achieved (Bank 1)Inspect for vacuum leaks, check the fuel pressure, and clean or replace the mass airflow sensor.
Code P1131Lack of Upstream Heated Oxygen Sensor Switch – Sensor Indicates Lean (Bank 1)Check for vacuum leaks, inspect the oxygen sensor, and address fuel delivery problems.
Code P1132Lack of Upstream Heated Oxygen Sensor Switch – Sensor Indicates Rich (Bank 1)Inspect the oxygen sensor, check for fuel pressure issues, and address vacuum leaks.
Code P1441Evaporative Emission Control System Flow During Non-PurgeInspect the evaporative emissions system for leaks and replace damaged components.
Code P1450Unable to Bleed Up Fuel Tank VacuumCheck the fuel tank pressure sensor and related components for issues. Repair or replace as needed.
Code P1518Intake Manifold Runner Control Fault – Stuck OpenInspect and clean the intake manifold runner control valve. Replace if necessary.
Code P1520Intake Manifold Runner Control Fault – Stuck ClosedInspect and clean the intake manifold runner control valve. Replace if necessary.

Read Best Chute Blocker for Scag Mowers(Best Top 5)

DIY Troubleshooting Tips

1. Checking for loose or damaged wires

Before diving into complex repairs, inspect the wiring harness for loose or damaged wires. Sometimes, a simple connection issue can trigger a check engine code.

2. Inspecting the Fuel System

If the code suggests a fuel-related problem, inspect the fuel system. Replace clogged filters and address issues with injectors or the fuel pump.

3. Examining the Ignition System

For ignition-related codes, examine the spark plugs and the ignition coil. Replacing worn-out spark plugs can often resolve misfire issues.

4. Addressing Exhaust System Concerns

Exhaust-related codes may indicate a problem with the catalytic converter or oxygen sensors. Addressing these issues promptly can improve engine performance.

Read Ferris Mower Year By Serial Number(Find Out Here)

When to seek professional help

While some issues can be resolved through DIY troubleshooting, certain complex problems may require professional intervention. If you’re unsure or uncomfortable with the repairs, it’s best to consult a qualified technician.

Maintenance Tips for Scag Mowers

Regular maintenance can help prevent engine codes. Follow Scag’s maintenance schedule, including oil changes, air filter replacements, and spark plug inspections, to keep your mower in top condition.

Read Spartan Mower Error 39 (3 Quick Ways to Fix)

Final Remarks

Scag check engine light codes may seem intimidating, but with the right knowledge and tools, you can diagnose and resolve many issues on your own. Understanding these codes empowers you to keep your Scag mower running smoothly and efficiently.


What should I do if my Scag mower’s check engine light comes on?

If the check engine light comes on, use a code reader to retrieve the specific code. Refer to your mower’s manual or online resources to interpret the code and take appropriate action.

Can I continue using my Scag mower if the check engine light is on?

It’s not recommended to continue using the mower with the check engine light on, as it may lead to further damage. It’s best to address the issue promptly.

Are Scag check engine codes universal, or do they vary by model?

Scag check engine codes can vary by model and engine type. It’s essential to refer to your specific mower’s manual or documentation for accurate code interpretation.

What are some routine maintenance tasks to prevent checking engine codes?

Routine maintenance tasks include changing the oil, replacing air filters, inspecting spark plugs, and following Scag’s recommended maintenance schedule.

Where can I find a code reader for my Scag mower?

You can find code readers for Scag mowers at auto parts stores, online retailers, or through authorized Scag dealerships.

George Bill
George Bill

George Bill is a Mechanical Engineer by Profession and an avid gardener and has been mowing his lawn for over 20 years. He has used a variety of different mowers during this time.
George is an expert at maintaining his mowers and over the years, he has learned many tricks and techniques for getting the best results from his mowers and is always happy to share his knowledge on this site.