Kohler Engine Diagnostics: Codes, Tools, and Troubleshooting Tips
Kohler engines are widely recognized for their durability and efficiency, powering everything from lawn mowers to generators. However, like any engine, they can encounter issues that require skilled diagnostics. In this blog, we’ll explore the key aspects of Kohler engine diagnostics, including the location of engine codes, the tools needed for effective troubleshooting, specific EFI diagnostics, and best practices for maintaining your Kohler engine in peak condition.
Where is The Kohler Engine Code?
The engine code generally provides essential information about the engine model, type, and specifications. This information plays a crucial role in troubleshooting and ordering the correct replacement parts or accessories. You can locate the engine code in a few common places:
Engine Block: Look on the front or side of the engine, typically near the starter or oil filter.
ID Tag: Many Kohler engines have an identification tag affixed to the engine. This tag usually contains the engine model and spec number, along with the engine code.
User Manual: The user manual often includes diagrams that show where to find the engine code for specific models.
Tools Required For Kohler Engine Diagnostics
Multimeter: A multimeter will check the electrical components of the engine, including battery voltage, continuity of wires, and other readings.
Jaltest or Kohler Diagnostic Tool: A specialized scanner can read the trouble codes stored in the engine's electronic control unit (ECU). This is especially necessary for Kohler engines with EFI systems. Request a demo of WholeFleet’s Jaltest software today.
Pressure Gauge: This tool is used to measure fuel pressure, ensuring the fuel system is operating correctly.
Compression Tester: A compression tester checks the engine's internal pressure, helping to diagnose potential issues with valves or piston rings.
Basic Hand Tools: Wrenches, screwdrivers, and pliers are essential for general maintenance, repairs, and the replacement of parts.
Kohler EFI Diagnostic
Kohler EFI (Electronic Fuel Injection) systems are designed to enhance engine performance and efficiency. However, when a problem arises within the EFI system, having a proper diagnostic approach is essential. Here are steps to perform EFI diagnostics on a Kohler engine:
Connect the Scanner: Start by connecting your Jaltest diagnostic tool or Kohler diagnostic tool to the engine’s diagnostic port. This will allow you to read any fault codes that may be present.
Check for Codes: Navigate through the scanner to retrieve any stored trouble codes. These codes will indicate where issues may exist within the engine.
Analyze Data: Pay attention to live data readings, such as fuel injector pulse width, throttle position, and engine temperature. Anomalies in these readings can help pinpoint problems.
Perform Tests: Depending on the codes retrieved, you may need to perform specific tests, such as checking the fuel pressure or inspecting the wiring and connectors related to the EFI system.
Clear Codes and Retest: After addressing any identified issues, clear the fault codes and perform a test run to see if the problem is resolved.
Regular EFI diagnostics not only help in promptly identifying issues but also ensure your engine operates efficiently over its lifespan.
Kohler Engine Fault Code List (2025 Update)
Fault Code SPN 91 FMI 2 - Invalid Data Received From Accelerator Pedal Module (U013C)
Meaning: The ECM is receiving faulty or inconsistent data from the accelerator-pedal module. The engine may not respond correctly to throttle input.
Troubleshooting: Inspect pedal module wiring and connectors, check for damage or corrosion, ensure connector pins are secure. Replace the pedal module if data remains invalid.
Fault Code SPN 102 FMI 2 - Turbocharger/Supercharger Boost System Performance (P2263)
Meaning: Boost pressure is off, the engine may run under-powered or with excessive smoke, or fail to deliver expected torque.
Troubleshooting: Check turbocharger function, inspect for boost leaks or exhaust restrictions, verify actuator or waste gate operation, and test related sensors (MAP, boost pressure).
Fault Code SPN 110 FMI 2 - Engine Coolant Flow Low/Performance (P00B7)
Meaning: Coolant circulation is insufficient, risk of overheating and engine damage.
Troubleshooting: Inspect coolant level, water pump operation, thermostat, coolant hoses, radiator blockage. Top-up coolant or repair/replace failed components.
Fault Code SPN 168 (FMI: 0/1/3/4/14/16/18) - System Voltage High / Low / Out-of-Range
Meaning: Electrical system voltage out of nominal range. Can impact performance of ECM, sensors, charging, battery, and overall engine operation.
Troubleshooting: Test battery health, alternator/regulator output, check grounds and wiring insulation; repair wiring or replace failing charging components.
Fault Code SPN 190 FMI 2 - Engine Speed Sensor Circuit Range/Performance (P0321)
Meaning: Irregular or missing RPM signal.
Troubleshooting: Check crankshaft (or camshaft) position sensor for damage, inspect tone wheel or reluctor ring, test wiring continuity, replace sensor if necessary.
Fault Code SPN 512 FMI 2 - Driver Demand Torque Check Error (U100D)
Meaning: The ECM detects erratic or inconsistent driver torque-request data. Throttle or torque request may not match actual engine behavior.
Troubleshooting: Inspect accelerator pedal module and wiring, verify CAN communication integrity, ensure no faults in torque-request messaging between modules.
Fault Code SPN 3217 FMI 2 - Invalid Data Received From NOx Sensor "A" (U1023)
Meaning: NOx sensor data invalid or corrupted. Risk of engine derate and emissions control malfunctioning.
Troubleshooting: Inspect NOx sensor wiring/connectors, check for contamination or damage, replace sensor if out of specification, verify ECM communication.
Fault Code SPN 3361 FMI 2 - Reductant Injection Valve Circuit Range/Performance (bank 1, unit 1) (P201A / P202E / P2057 / P2058)
Meaning: DEF tank reductant injection valve or circuit fault.
Troubleshooting: Check valve wiring, inspect for shorts or opens, test valve actuation, replace valve or repair circuit as needed.
Fault Code SPN 3241 FMI 3 or 4 - Exhaust Gas Temperature (EGT) Sensor Circuit High/Low (Bank 1 Sensor 2) (P2032 / P2033)
Meaning: EGT sensor reporting extreme or invalid temperatures.
Troubleshooting: Inspect sensor wiring/connectors, check for heat damage or wiring melt, test sensor resistance/voltage, replace sensor if malfunctioning.
Fault Code SPN 1562 FMI 14 - Not Programmed DCU Detected (P0602)
Meaning: The DEF dosing control unit (DCU) is not properly programmed. The DEF/after-treatment system will be disabled or operate incorrectly.
Troubleshooting: Re-program DCU per manufacturer instructions, check firmware version, ensure ECM recognizes DCU, or replace DCU if needed.
Best Practices For Keeping Your Kohler Engine In Top Condition
It’s recommended that you take proactive and preventative action to maintain your Kohler engine’s health. Whether you do will have an impact on your engine’s life span. Here are the best practices for keeping the health of your Kohler engine in check.
Regular Oil Changes: Change the oil and oil filter according to the manufacturer’s recommendations. Fresh oil ensures that the engine runs smoothly and reduces wear, prolonging your engine’s overall life span.
Check Air Filters: Clean or replace air filters regularly to prevent dirt and debris from entering the engine, which can affect performance.
Inspect Spark Plugs: Regularly check and replace spark plugs as needed to maintain efficient ignition and fuel burn.
Maintain Fuel System: Use high-quality fuel and consider adding fuel stabilizers if the engine will sit unused for an extended period. Regularly check for any signs of leaks or corrosion in fuel lines.
Routine Inspections: Conduct regular physical inspections of the engine, checking for loose bolts, worn belts, and electrical connections. This helps catch potential issues early.
Keep the Engine Clean: Regularly clean the engine exterior to prevent dirt buildup, which can lead to overheating and other issues.
Why Choose Jaltest Diagnostic Software?
Jaltest is the ultimate solution to diagnosing and maintaining your vehicle. What makes Jaltest different from other diagnostic tools is that its coverage spans across multiple types of vehicles, models, and systems. While other diagnostic software like Kohler’s EFI Diagnostic tool supports only the vehicles made by their own brand, Jaltest supports multiple brands of vehicles, with continuous updates to account for growing companies and innovations across industries. Supported by a user-friendly and intuitive software interface, Jaltest can service multiple vehicles, no matter the make, model, or brand.
Interested in learning more? Take a look at our pricing guide or contact us to find out if Jaltest is right for you.
