Mercury Smartcraft Fault Codes List — Working & Full

The battery voltage is above the normal limit. Return to port immediately for service.

Seeing a code is step one. Fixing it requires logic. Follow this workflow: mercury smartcraft fault codes list

| Code | Description | Likely Cause | Guardian Mode? | |------|-------------|--------------|----------------| | | Crank Position Sensor | Sensor failure, wiring issue, or gap incorrect | Yes – no start or stall | | 14 | Coolant Temperature Sensor high voltage | Open circuit, bad sensor, or connector corrosion | No – but fuel mixture affected | | 21 | Intake Air Temp Sensor low voltage | Short to ground, bad sensor | No | | 22 | Intake Air Temp Sensor high voltage | Open circuit, bad sensor | No | | 24 | Manifold Absolute Pressure (MAP) sensor | Vacuum leak, wiring, or failed sensor | Yes – reduced power | | 33 | Throttle Position Sensor (TPS) range error | Mismatch between TPS1 and TPS2, or binding throttle | Yes – limp mode | | 34 | TPS circuit low voltage | Short to ground, bad ground | Yes | | 35 | TPS circuit high voltage | Open circuit, reference voltage issue | Yes | | 42 | Knock Sensor circuit | Bad sensor, wiring, or detonation detected | Yes – timing retard | | 44 | Oxygen Sensor (O2) – lean condition | Vacuum leak, fuel pressure low, O2 sensor failed | No | | 45 | Oxygen Sensor (O2) – rich condition | Injector leak, high fuel pressure, MAP/MAF issue | No | | 51 | Fuel Pump circuit | Relay, fuse, wiring, or pump failure | Yes – engine may stall | | 52 | Injector circuit – cylinder 1 | Open or short in injector driver or wiring | Yes – misfire | | 53 | Injector circuit – cylinder 2 | Same as above | Yes | | 54 | Injector circuit – cylinder 3 | Same as above | Yes | | 55 | Injector circuit – cylinder 4 | Same as above | Yes | | 61 | Ignition coil – primary circuit | Coil failure, driver circuit, or wiring | Yes – misfire | | 71 | Engine Overheat (critical) | Water pump impeller, thermostat, blocked intake | Yes – RPM reduction to ~2500 | | 72 | Engine Overheat (warning) | Same as above, lower temp threshold | No – alarm only | | 81 | Low Oil Pressure | Pressure switch, actual low oil, or pump failure | Yes – Guardian active | | 91 | Battery Voltage high (over 16V) | Regulator/rectifier failed | Yes – possible electrical damage | | 92 | Battery Voltage low (under 9V) | Charging system, loose battery cable, dead battery | No – erratic gauge readings | | 101 | Shift interlock fault | Shift actuator, neutral safety switch | Yes – will not start or shift | | 112 | CAN bus communication loss (engine to gauge) | Wiring, terminator, or gauge failure | No – gauges freeze/blank | | 121 | ECM internal fault | Corrosion, voltage spike, or ECM failure | Yes – severe limp mode | | 122 | Guardian Engine Protection active | See root cause code (overheat, oil, knock, etc.) | Yes – RPM limited | | 151 | Fuel pressure sensor out of range | Sensor failed, fuel restriction, or pump issue | Yes | | 201 | Steering angle sensor not calibrated | After service, or sensor disconnected | No – DTS only | | 202 | DTS (Digital Throttle & Shift) calibration lost | Battery disconnected, ECU reset | No – shift issues | The battery voltage is above the normal limit

Oil pump has stopped functioning electrically. No lubrication is being supplied. Overheat Protection Fixing it requires logic

Mercury SmartCraft fault codes alert you to engine issues ranging from sensor malfunctions to critical cooling or oil failures . When a fault occurs, the "AL" alarm

These are the most common codes related to air, fuel, and ignition.

If and engine runs fine, clear the code and monitor. Do not replace parts for a historic code.