Case IH 2700 (6583.03) - DEC – ECM / TCM / VCU: Ma Pressure Sensor - Signal wire shortcut to VSupply

The fault indicates a short circuit to the voltage supply (VSupply) on the signal circuit of the 'Ma Pressure Sensor' (Manifold Absolute Pressure or Main Pressure Sensor). The ECU is seeing a constant high voltage on the sensor's signal return pin.

• VESTRUM CVX
• Magnum
• Steiger
• Puma
• Maxxum
• Axial-Flow 7240
• Axial-Flow 8240
• Axial-Flow 9240
• Patriot
• MX180
• MX200
• MX220
• MX240
• MX270
• Quadtrac

1. 1

   Visual Inspection: Inspect the wiring harness leading to the sensor for rubbed-through insulation, pinched wires, or melted conduit where the 5V supply wire could be touching the signal wire.

2. 2

   Connector Check: Disconnect the sensor and inspect the pins inside the connector for corrosion, water ingress, or bent pins that might be bridging the 5V and signal terminals.

3. 3

   Voltage Test: With the sensor disconnected and the key ON, use a multimeter to measure the voltage on the signal wire at the harness connector. If it reads ~5V, the short is in the wiring harness. If it reads 0V, the wiring is likely fine and the sensor itself is internally shorted.

1. 1

   Disconnect battery

   Turn off the machine and disconnect the battery ground.

2. 2

   Repair damaged harness (if applicable)

   If the harness is damaged, trace it back from the sensor to locate the short. Cut out the damaged section of wiring and splice in new wire using weather-sealed, heat-shrink butt connectors. Secure the harness with zip ties away from high-heat or high-vibration areas.

3. 3

   Relieve system pressure (if replacing sensor)

   If the sensor is faulty, turn off the machine and relieve any system pressure (if it is a hydraulic main pressure sensor).

4. 4

   Remove faulty sensor

   Disconnect the electrical connector from the sensor. Use a deep socket or wrench to carefully unthread the faulty sensor.

5. 5

   Install new sensor

   Lubricate the O-ring on the new sensor with clean system fluid (engine oil or hydraulic fluid). Thread the new sensor in by hand to prevent cross-threading, then tighten to the OEM torque specification.

6. 6

   Reconnect and clear codes

   Reconnect the electrical harness. Reconnect the battery, turn the key ON, and use a diagnostic tool (like the Case IH EST) to clear the inactive fault code.