Case IH 5011 – INST or INST2: Engine Oil Pressure sensor voltage is too low (open circuit, short to ground)

The engine oil pressure sensor signal voltage falls out of its normal operating range on the low side. Specifically, the system logs this fault if the signal drops below 0.25 volts for 1 second.

• MX Magnum
• STX Steiger
• MX Magnum series
• TG series
• Steiger series
• Puma series
• Maxxum series
• Farmall series
• Various Case loaders and excavators

1. 1

   Measure the engine oil pressure sensor's internal resistance using a multimeter to determine if the sensor itself has failed internally

2. 2

   Inspect the wiring harness running from the instrumentation controller (INST) to the engine oil pressure sensor

3. 3

   Test the circuit for an open connection or a short to ground

4. 4

   If the sensor and wiring harness both test within specification, check for an Instrument Controller failure

1. 1

   Locate the Sensor

   Find the engine oil pressure sensor on the engine block.

2. 2

   Inspect the Connection

   Disconnect the sensor pigtail. Check the connector pins for corrosion, moisture, or pushed-back pins.

3. 3

   Test the Sensor

   Using a multimeter, check the resistance across the sensor terminals. If the resistance is out of OEM specification (or reads completely open/shorted), the sensor is faulty and must be replaced.

4. 4

   Test the Harness

   If the sensor tests good, use your multimeter to check the signal wire, 5V reference (supply), and ground wire between the sensor connector and the Instrument Controller (INST). Look for voltage drops or continuity to ground indicating a short.

5. 5

   Repair Wiring

   Repair any chafed wires or replace the damaged harness section if an open circuit or short to ground is found.

6. 6

   Replace Controller (Last Resort)

   If the sensor and wiring are perfectly intact and the voltage drop persists at the module level, the Instrument Controller may require replacement or reprogramming.

7. 7

   Clear Codes

   Reconnect all components, clear the fault codes from the INST module, and run the engine to verify that the oil pressure reads correctly and the code does not return.