Case IH t67 – Engine Control Unit (ECU) or Powertrain Control Unit (PCU): IAT System, Data Valid But Above Normal Range

The Intake Air Temperature (IAT) sensor is sending a valid electrical signal to the control module, but the temperature reading being reported is higher than the normal operating threshold. This indicates either an actual high intake air temperature condition (such as a restricted intercooler or turbocharger issue) or a skewed/defective sensor reporting artificially high temperatures.

• MXM
• MXM Series
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190
• TM115-TM165
• Maxxum
• Puma
• Steiger
• Axial-Flow Combines

1. 1

   Verify actual intake manifold air temperature to ensure the engine is not genuinely running hot due to a blocked charge air cooler (intercooler), extreme ambient heat, or a failing turbocharger.

2. 2

   Compare the IAT sensor reading with the ambient air temperature when the engine is completely cold. If the sensor reads significantly higher than ambient temperature, the sensor is skewed and defective.

3. 3

   Inspect the IAT sensor wiring harness and the in-line electrical connector for corrosion, loose pins, or chafing (high resistance can skew readings).

1. 1

   Turn off engine

   Turn off the engine, ensure the key switch is in the OFF position, and allow the engine to cool.

2. 2

   Locate sensor

   Locate the Intake Air Temperature (IAT) sensor. On many CNH/FPT engines, this is a combined MAP/IAT sensor located on the intake manifold or air intake piping.

3. 3

   Disconnect connector

   Disconnect the in-line electrical connector from the IAT sensor.

4. 4

   Detach wiring harness

   Detach the wiring harness from any retaining clips to provide clearance and prevent wire strain.

5. 5

   Remove sensor

   Remove the faulty IAT sensor from the manifold.

6. 6

   Install new sensor

   Install the new IAT sensor and secure it.

7. 7

   Reconnect wiring

   Reconnect the electrical connector and secure the wiring harness back into its clips.

8. 8

   Clear fault codes

   Turn the key switch to ON, enter the tractor's diagnostic system (H-menu), and clear the fault codes. Run the engine to verify the code does not return.