New Holland ENG 3517 – Engine Control Unit (ECU): Air Filter Temperature Sensor: Ambient Air Temperature Sensor failure (of Humidity Sensor if installed) - Signal too high

The voltage signal returning from the ambient air temperature/humidity sensor (located in the engine air intake system) is exceeding the maximum expected threshold. This typically indicates an open circuit in the sensor wiring, a short to a power source, or an internally failed sensor.

• L220
• SR175
• B90B
• B100B
• T5
• T6
• T7
• T7.175
• T7.190
• T7.200
• T7.220
• T7.250
• T8
• T9
• CR6090
• CR9090
• CX8080
• CX8090
• Magnum 235-340
• Vestrum

1. 1

   Inspect the wiring harness and connector at the Air Filter Temperature / Humidity Sensor for physical damage, corrosion, or loose/pushed-out pins.

2. 2

   Check for an open circuit or a short-to-voltage in the sensor signal wire leading back to the Engine ECU.

3. 3

   Verify that the sensor is receiving the correct 5V reference and has a solid ground at the connector.

4. 4

   Check the engine air intake piping for any physical damage or blockages that might affect sensor readings.

5. 5

   Clear the code with a diagnostic tool. If it returns immediately upon key-on, it is a hard electrical fault (wiring or dead sensor). If it returns only during operation or vibration, suspect an intermittent wiring short or chafe.

1. 1

   Turn off the machine, remove the key, and disconnect the battery ground cable to ensure safety and prevent electrical spikes.

2. 2

   Locate the Air Filter Temperature / Humidity Sensor.

   It is mounted directly on the engine air intake hose/piping assembly (often between the air filter housing and the turbocharger).

3. 3

   Depress the locking tab and disconnect the electrical harness connector from the sensor.

4. 4

   Remove the faulty sensor from the air intake pipe.

5. 5

   Install the new OEM sensor into the intake piping.

   Ensure that any O-rings or seals are properly seated to prevent unmetered dust or air from entering the engine intake.

6. 6

   Reconnect the electrical harness connector until it clicks securely into place.

7. 7

   Reconnect the battery, turn the key on, and use a CNH diagnostic tool (EST) to clear the ENG 3517 fault code.

8. 8

   Start the engine and verify that the code does not return and that the intake temperature/humidity readings on the diagnostic tool are plausible.