Modern marine engines are data centers on water. Mercury Marine’s digital integration system is the nerve center—monitoring everything from engine temperature to fuel efficiency. But when something goes wrong, SmartCraft speaks in alphanumeric codes. Understanding these codes is the first step to a swift, safe repair.
| Fault Code | Description | Typical Cause / Action | | :--- | :--- | :--- | | | Engine Temperature Sensor Fault | Open or short circuit in the temperature sensor. Check wiring harness for corrosion or breaks. | | Code 2 | Throttle Position Sensor (TPS) Fault | Signal out of range. Often caused by a faulty TPS or loose connection at the throttle body. | | Code 3 | Oil Level Sensor Fault | Detected low oil or sensor failure. Check oil tank level; if full, inspect sensor float for sticking. | | Code 4 | Exhaust Gas Temperature (EGT) Sensor | High exhaust temp or sensor failure. Common in Verado models. Check for cooling blockages. | | Code 5 | Barometric Pressure Sensor | Sensor internal to ECU (or external on older models) providing inaccurate data. Can cause rough running at altitude. | | Code 6 | Crankshaft Position Sensor | No signal detected. Engine may crank but not start. Check air gap and wiring. | | Code 7 | Camshaft Position Sensor | Sync signal error. Usually results in a no-start condition or limp mode. | | Code 8 | Knock Sensor Fault | Open or short circuit. Can result in the ECU retarding timing unnecessarily (power loss). | mercury smartcraft fault codes list
| Code | SPN | FMI | Description | |------|-----|-----|-------------| | 12-1 | 110 | 1 | Engine coolant temperature sensor – voltage too low (shorted) | | 12-2 | 110 | 0 | Coolant temp sensor – voltage too high (open circuit) | | 13-1 | 105 | 1 | Intake air temp sensor – voltage low | | 13-2 | 105 | 0 | Intake air temp sensor – voltage high | | 15-1 | 174 | 1 | Fuel temperature sensor – voltage low | | 15-2 | 174 | 0 | Fuel temp sensor – voltage high | | 22-1 | 100 | 1 | Oil pressure sensor – voltage low | | 22-2 | 100 | 0 | Oil pressure sensor – voltage high | | 23-1 | 100 | 1 | Low oil pressure (actual) – engine may shut down | | 31-1 | 157 | 0 | MAP sensor (Manifold Absolute Pressure) – voltage high | | 31-2 | 157 | 1 | MAP sensor – voltage low | Modern marine engines are data centers on water
Fault codes are typically categorised by the severity of the issue, ranging from minor sensor glitches to critical mechanical failures that trigger the to limit power. Code / Fault Meaning & Possible Cause Recommended Action Code 1 High Battery Voltage : System detects over-charging. Understanding these codes is the first step to
: Signal failure to specific ignition coils. Inspect spark plugs, coils, and ECU wiring harness. Code 201–203 Fuel Injector Circuit : ECM cannot signal fuel injectors. Check injector wiring and fuel system pressure. Code 2011-23 Data Communication Error : Communication loss with ECM. Inspect NMEA 2000 or SmartCraft cable connections. Code 3014-6 Engine Speed Sensor : Faulty RPM data. Clean sensor tip or check wiring for corrosion. How to Read and Diagnose Faults