Case IH 2 – EIC (Electronic Instrument Cluster) / Digital Instruments: Critical short to a +ve Voltage in the Engine Oil Pressure Sender circuit

The controller is receiving a voltage signal from the oil pressure sender that is higher than the maximum expected threshold. This typically occurs when the sensor's signal wire is shorted directly to a power source (such as a 12V wire in the harness), or the sensor itself has suffered an internal failure that bridges the supply voltage directly to the signal return.

• MXM
• MXM Series
• MXM120
• MXM130
• MXM140
• MXM155
• MXM175
• MXM190

1. 1

   Visually inspect the wiring harness leading to the engine oil pressure sender for signs of chafing, melting, or pinched wires that could cause a short to a 12V power wire.

2. 2

   Disconnect the oil pressure sender and inspect the connector for water ingress, dirt, or corrosion bridging the voltage supply pin to the signal pin.

3. 3

   Perform a circuit isolation test: with the sensor disconnected, turn the key ON and check the active fault codes on the EIC. If the code changes to Code 1, the sensor is internally shorted. If Code 2 remains active, the short is in the wiring harness.

4. 4

   Use a multimeter to measure the voltage on the signal wire at the sensor connector (with the sensor unplugged). A reading of 12V confirms a wiring harness short.

1. 1

   Prepare machine

   Ensure the tractor engine is off, the key is removed, and the machine has cooled down.

2. 2

   Locate sender

   Locate the engine oil pressure sender on the engine block (typically threaded directly into the block near the oil filter housing or injection pump).

3. 3

   Disconnect connector

   Disconnect the electrical spade or pin connector from the sender.

4. 4

   Repair wiring (if applicable)

   If repairing wiring: Trace the harness back toward the EIC, locate the shorted section, splice in new wire using weather-sealed heat shrink connectors, and re-loom the harness.

5. 5

   Remove old sensor (if replacing)

   If replacing the sensor: Use a wrench or deep socket to unthread the old oil pressure sender from the engine block. Have a rag ready to catch minor oil drips.

6. 6

   Prepare new sensor

   Apply a liquid thread sealant or Teflon tape to the threads of the new sensor (unless it comes with pre-applied sealant or a crush washer/seal ring).

7. 7

   Install new sensor

   Thread the new sensor into the block by hand to prevent cross-threading, then tighten to the manufacturer's torque specification.

8. 8

   Reconnect connector

   Reconnect the electrical connector, ensuring it clicks into place securely.

9. 9

   Verify repair

   Turn the key ON, clear the fault codes from the EIC, and start the engine to verify that the oil pressure warning light goes out, the code does not return, and no leaks are present at the sensor threads.