Cummins fault code 212

What it means

Cummins' description: Engine Oil Temperature Sensor 1 Circuit - Voltage above normal, or shorted to high source.

SPN 175 is Engine Oil Temperature 1. FMI 3 means the voltage on the circuit is higher than possible for a good sensor, usually an open signal wire, a short to a power wire, or a failed sensor.

The ECM monitors oil pressure, oil temperature and, on some engines, oil level. Low oil pressure is one of the fastest ways to destroy an engine, so Cummins treats it very seriously.

What the lamp means

An amber (yellow) warning lamp means the engine can usually keep running, but the fault should be repaired soon, ideally the same day.

Common causes

FMI 3 is an electrical or signal fault, so start with the circuit:

• Oil pressure or temperature sensor failed
• Connector or wiring problem at the sensor

If the circuit checks out, the reading may be real. Other possibilities: low oil level; wrong oil viscosity or diluted oil (fuel or coolant in the oil); worn oil pump or bearings.

What you can check before calling

• Check the oil level with the engine off and level
• Look at the oil for milky color (coolant) or a fuel smell
• Note whether the oil gauge drops at hot idle

Clearing the code without fixing the cause usually brings it right back, and on emissions systems it can restart derate timers.

Engines and sources

Listed by Cummins for: QSX 15, QSG 12. Cummins uses the same fault code numbers across its electronic engines, including on-highway models like the ISB/B6.7, ISL/L9 and ISX/X15, though not every code applies to every engine or software level. Source: Cummins Tier 4 Fault Codes. Always confirm with Cummins service information (QuickServe) for your engine serial number.