Case IH 3532 – Engine Control Unit (ECU): NOx Sensor Failure - Sensor not ready in time

The Nitrogen Oxide (NOx) sensor failed to reach its operational readiness state within the timeframe expected by the computer after engine startup, likely due to an internal heater failure or sensor degradation.

• Magnum (180 to 380)
• Steiger / Quadtrac (350 to 620)
• Puma (150 to 220)
• Maxxum (115 to 150)
• Farmall A-Series (110A to 170A)
• Axial-Flow 5130
• Axial-Flow 6130
• Axial-Flow 7130
• Axial-Flow 7230
• Axial-Flow 8230
• Axial-Flow 9230
• Titan 2240
• Titan 3030
• Titan 3530
• Titan 4030
• Titan 4530
• Case Wheel Loader 521F
• Case Wheel Loader 621F
• Case Wheel Loader 821F
• Case Wheel Loader 921F
• Case Wheel Loader 1021F
• Case Wheel Loader 1121F

1. 1

   Check for accompanying codes (e.g., 3529, 3530, or 3533) to determine if the issue is a wiring or communication failure rather than a slow-to-heat sensor.

2. 2

   Visually inspect the NOx sensor wiring harness and connector for heat damage, melting, or corrosion.

3. 3

   Verify that the sensor is receiving proper supply voltage (power and ground) to ensure the internal heater can function.

1. 1

   Disconnect battery

   Turn off the machine and disconnect the battery via the master disconnect switch to prevent electrical shorts.

2. 2

   Locate sensor

   Locate the faulty NOx sensor on the exhaust/SCR catalyst pipe.

3. 3

   Disconnect harness

   Disconnect the electrical connector from the machine's wiring harness.

4. 4

   Remove sensor

   Carefully unscrew the NOx sensor from the exhaust pipe. Apply penetrating oil and allow it to soak to avoid stripping the exhaust bung threads.

5. 5

   Install new sensor

   Install the new NOx sensor and tighten it to the OEM specified torque.

6. 6

   Route wiring and reconnect

   Route the wiring safely away from direct heat sources and reconnect the electrical harness.

7. 7

   Clear codes

   Turn on the battery and use a diagnostic scan tool to clear the error codes so the machine exits any active torque derate/limitation modes.