New Holland ENG 3715 – Engine Control Unit (ECU) / Electronic Diesel Control (EDC): Lambda Sensor: Fault code to indicate SRC Low error for O2 calibration.

The engine control system performs a calibration of the Lambda (Oxygen/O2) sensor where the measured oxygen signal must be lower than 0.2 Volts. This fault code is triggered when the oxygen signal is greater than 0.2 V during the calibration process.

• T4 (PowerStar)
• T5
• T6
• T7
• Boomer series
• CR9090
• CX8080 Elevation
• CX8090 Elevation
• L-Series
• C-Series
• L230
• L185
• C185

1. 1

   Verify Active Code: Confirm that the fault code is currently active and not a stored historical code.

2. 2

   Wiring and Connection Inspection: Inspect the electrical wiring harness and the connector at the Lambda sensor. Look for chafed wires, short circuits, corrosion, or loose pins that could be artificially inflating the voltage reading.

3. 3

   Check Related Systems: Ensure there are no underlying problems with the fuel injection system or the Exhaust Gas Recirculation (EGR) system, as these can alter exhaust oxygen levels and cause calibration failures.

4. 4

   Software Check: Verify if there are any pending ECU software updates from New Holland, as software glitches can occasionally cause calibration errors.

1. 1

   Power Down

   Turn off the machine and disconnect the battery ground to ensure safety while working on the exhaust and electrical systems.

2. 2

   Locate the Sensor

   Locate the Lambda (O2) sensor, which is typically threaded into the exhaust stream before the catalytic converter / Diesel Oxidation Catalyst (DOC).

3. 3

   Disconnect and Inspect

   Unplug the sensor's electrical connector (often a 4-wire or 5-wire connector). Check the pins for moisture or soot intrusion.

4. 4

   Remove the Sensor

   Using an O2 sensor socket or wrench, carefully unthread the faulty Lambda sensor from the exhaust pipe. (Penetrating oil may be required if the sensor is seized).

5. 5

   Install the New Sensor

   Thread the new OEM Lambda sensor into the exhaust housing. Tighten to the manufacturer's specified torque to prevent exhaust leaks.

6. 6

   Reconnect

   Plug the electrical connector back into the engine harness, ensuring it clicks securely into place.

7. 7

   Clear Codes and Test

   Reconnect the battery, use a diagnostic tool (like the CNH Electronic Service Tool) to clear the ENG 3715 fault code, and run the engine. Allow the system to perform its O2 calibration to verify the repair is successful.