Case IH 227 – Engine Control Module (ECM) or Motor Control Module (MCM): Sensor Supply 2 Circuit – Voltage Above Normal or Shorted to High Source

The 5-volt reference circuit (Sensor Supply 2) is detecting a voltage higher than normal (typically greater than 5.3 volts). This usually means the 5-volt supply wire is shorted to a higher voltage source, such as a 12-volt battery circuit, either internally within a sensor or externally in the wiring harness.

• MX Magnum
• STX Steiger
• MX Magnum Series
• TG Series
• Puma Series
• AFX8010
• QSB 4.5
• QSB 6.7
• QSL 9
• QSX 15
• ISM
• ISX

1. 1

   Connect an electronic service tool (Case IH EST or Cummins INSITE) and check if any specific sensor codes are active alongside code 227.

2. 2

   Perform a disconnect test: Turn the ignition ON (Engine OFF). While monitoring the active fault code 227, disconnect the sensors on the Sensor Supply 2 circuit one at a time (typically Engine Oil Pressure, Camshaft Position, Accelerator Pedal Position 2, Fuel Compensation/HC Doser Fuel Pressure, and Fan/Water Pump Speed sensors).

3. 3

   Monitor the code during the disconnect test: If fault code 227 goes inactive when a specific sensor is disconnected, that sensor has an internal short to voltage.

4. 4

   Inspect the engine wiring harness: If the code remains active after all sensors are unplugged, inspect the harness connectors and ECM pins (e.g., pin 82) for bent/spread pins, corrosion, moisture, or rubbed wires shorting to a 12V source.

1. 1

   Power Down

   Turn the ignition switch to the OFF position before replacing any components or repairing wiring.

2. 2

   Address the Short

   If a sensor failed the disconnect test: Replace the internally shorted sensor. If the harness failed: Locate the short-to-power in the Sensor Supply 2 wiring. Repair the damaged wire or replace that section of the engine wiring harness.

3. 3

   Reassemble

   Reconnect all sensors and ensure harness connectors are fully seated and locked.

4. 4

   Clear Codes

   Turn the ignition ON. Use the 'Reset All Faults' command in your electronic service tool to clear the inactive fault code and extinguish the amber Check Engine / Malfunction Indicator Lamp (MIL).