New Holland ENG 3713 – Engine ECU: Lambda Sensor: Open Load error of the LSU Heater Power stage

The engine control system has detected an 'open load' (an open electrical circuit or infinite resistance) in the heater circuit of the Lambda (Oxygen/O2) sensor. This indicates the heater element inside the sensor is likely burned out, or there is a broken wire/disconnected plug preventing power from reaching the heater.

• L216
• L218
• L220
• L225
• L234
• SR175
• SV185
• W50C
• W60C
• W70C
• W80C
• B95B
• B115B
• T6030
• TL80A
• TL90A
• TD5.115

1. 1

   Check the Lambda sensor electrical connector to ensure it is fully seated and not disconnected.

2. 2

   Inspect the wiring harness between the Lambda sensor and the Engine ECU for severed wires, chafing, or corroded pins that could cause an open circuit.

3. 3

   Using a multimeter, check the resistance across the heater pins on the Lambda sensor itself. If the reading shows 'OL' (Open Line / infinite resistance), the internal heater element has failed.

1. 1

   Turn off the machine's ignition and disconnect the battery to prevent electrical shorts.

2. 2

   Locate the Lambda (O2) sensor on the machine's exhaust system.

3. 3

   Disconnect the electrical harness connector from the Lambda sensor.

4. 4

   Using an appropriate O2 sensor socket or wrench, carefully unthread and remove the faulty Lambda sensor from the exhaust pipe.

5. 5

   Install the new Lambda sensor into the exhaust and tighten it to the OEM torque specification.

6. 6

   Reconnect the sensor's electrical harness connector, ensuring it clicks securely into place.

7. 7

   Reconnect the battery.

8. 8

   Connect a diagnostic service tool to the machine, clear the fault codes, and perform a 'Reset ECU data (Lambda sensor)' configuration procedure.

   This is required so the Engine ECU recognizes the new sensor.

9. 9

   Start the engine and verify that fault code ENG 3713 does not return.