Case IH 3716 – Engine Control Unit (ECU) / Electronic Diesel Control (EDC) or Aftertreatment Control Module: Lambda sensor: O2 value above the max threshold / DPF Active Regeneration Inhibited Due to Engine Not Warmed Up

Fault code 3716 indicates either that the oxygen sensor (lambda probe) in the exhaust system is reading an oxygen concentration that is implausibly high, or that the engine coolant temperature has not reached the required thermal threshold to allow an active DPF regeneration to safely occur.

• skid steer
• Case IH tractors
• skid steer loaders (SSL)
• compact track loaders (CTL)
• Maxxum 135
• Maxxum 145
• Maxxum 150
• Farmall 95U
• Farmall 105U
• Farmall 115U Pro EP
• Puma
• Steiger
• CX series

1. 1

   Lambda (O2) Sensor: Visual Inspection - Check the wiring harness and connectors leading to the lambda sensor for melting, chafing, corrosion, or loose pins.

2. 2

   Lambda (O2) Sensor: Voltage Check - Verify the battery voltage at the SPI chip, as related voltage codes (like 3720) often accompany this fault if there is an electrical supply issue.

3. 3

   Lambda (O2) Sensor: Exhaust Leak Test - Inspect the exhaust system for leaks upstream of the O2 sensor.

4. 4

   Lambda (O2) Sensor: Live Data - Use the CNH Electronic Service Tool (EST) to monitor the live O2 sensor data to see if the sensor is stuck at a high value or responding sluggishly.

5. 5

   DPF / Coolant Temp: Coolant Level - Check the engine coolant reservoir to ensure the system is full.

6. 6

   DPF / Coolant Temp: Sensor Verification - Verify the operation of the engine coolant temperature (ECT) sensor. Ensure it is reading accurately and not stuck at a low temperature.

7. 7

   DPF / Coolant Temp: Thermostat Check - Inspect the engine thermostat. If it is stuck open, the engine will overcool and fail to reach the operating temperature required for DPF regeneration.

1. 1

   Lambda Sensor: Cool exhaust system

   Turn off the machine and allow the exhaust system to cool completely to avoid burns.

2. 2

   Lambda Sensor: Disconnect battery

   Disconnect the negative battery cable.

3. 3

   Lambda Sensor: Locate lambda sensor

   Locate the lambda sensor on the exhaust pipe/aftertreatment system.

4. 4

   Lambda Sensor: Disconnect sensor connector

   Disconnect the electrical connector for the sensor.

5. 5

   Lambda Sensor: Remove lambda sensor

   Use a specialized O2 sensor socket to carefully unscrew the sensor from the exhaust bung.

6. 6

   Lambda Sensor: Apply anti-seize

   Apply a small amount of high-temp anti-seize compound to the threads of the new sensor (if not pre-applied by the manufacturer). Caution: Do not get anti-seize on the sensor tip.

7. 7

   Lambda Sensor: Install new lambda sensor

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

8. 8

   Lambda Sensor: Reconnect components

   Reconnect the electrical connector and the battery.

9. 9

   Lambda Sensor: Clear codes and verify

   Clear the fault codes using the CNH EST diagnostic tool and run the engine to verify the code does not return.

10. 10

    Coolant/DPF Issue: Replace thermostat

    If the thermostat is stuck open, drain the coolant, replace the thermostat, and refill/bleed the cooling system.

11. 11

    Coolant/DPF Issue: Replace coolant temperature sensor

    If the coolant temperature sensor is faulty, disconnect its harness, unscrew the old sensor, install the new sensor, and reconnect the harness.

12. 12

    Coolant/DPF Issue: Initiate DPF regeneration

    Run the engine to operating temperature and initiate a manual/parked DPF regeneration using the machine's display or diagnostic tool to clear the soot load.