Case IH 1801 – Engine Control Unit (ECU): ISM-IDI DOC Intake Temperature Sensor Out Of Range High

The engine control system is receiving a signal from the Diesel Oxidation Catalyst (DOC) Intake Temperature Sensor that exceeds the maximum expected voltage or resistance threshold, indicating an open circuit.

• skid steer
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• SR130
• SR160
• SV185

1. 1

   Inspect the DOC Intake Temperature Sensor and its wiring harness for melted wires, chafing, or a disconnected plug

2. 2

   Disconnect the sensor and inspect the pins for corrosion, moisture, or bent terminals

3. 3

   Using a multimeter, measure the resistance across the sensor's pins (an 'OL' or infinite reading indicates internal failure)

4. 4

   Turn the key to the ON position (engine off) and check the harness side of the connector for the ECU's 5V reference signal and ground. If the reference voltage is missing, trace the harness back to the Engine ECU to locate the broken wire.

1. 1

   Safety First

   Turn off the machine and allow the exhaust system to cool completely. The DOC and DPF assembly operate at extreme temperatures and can cause severe burns.

2. 2

   Locate the Sensor

   Locate the DOC Intake Temperature Sensor. It is threaded into the exhaust pipe directly upstream of the Diesel Oxidation Catalyst (DOC) housing.

3. 3

   Disconnect Wiring

   Unplug the electrical connector from the sensor harness.

4. 4

   Remove the Sensor

   Using a properly sized wrench or sensor socket, carefully unscrew the sensor from the exhaust pipe. Note: Exhaust sensors frequently seize; apply penetrating oil to the threads and allow it to soak if the sensor is stuck.

5. 5

   Prepare the New Sensor

   Apply a small amount of high-temperature anti-seize compound to the threads of the new sensor (if it does not come pre-coated from the factory). Do not get anti-seize on the sensor probe itself.

6. 6

   Install the Sensor

   Thread the new sensor in by hand to prevent cross-threading, then tighten it securely to OEM torque specifications.

7. 7

   Reconnect

   Plug the electrical connector back into the machine's harness, ensuring the locking tab clicks into place.

8. 8

   Clear Codes

   Turn the ignition on. Use the Case Electronic Service Tool (EST) to clear the fault codes, or run the engine to verify if the ECU self-clears the active code to a logged/inactive state.