Case IH 19258 – Engine Control Unit (ECU): Physical Range Check low for Engine coolant temperature (down stream)

The physical signal from the downstream engine coolant temperature sensor falls below the minimum acceptable limit (SRC low), indicating that the sensor is defective or there is a short circuit to ground in the sensor's circuit.

• Tier 4b
• T7 Series
• Puma
• Optum
• N-Series Tractor Loader Backhoes
• 580N

1. 1

   Visually inspect the wiring connector at the downstream Charge Air Cooler / engine coolant temperature sensor for corrosion, damage, or loose pins

2. 2

   Test the sensor supply voltage and check the wiring harness for a short circuit to ground

3. 3

   If the wiring harness is intact and no short to ground is found in the chassis wiring, test the sensor itself for an internal short or failure

1. 1

   Turn off the machine and disconnect the battery

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

2. 2

   Locate the sensor

   Locate the downstream engine coolant temperature sensor on the engine block/cooling circuit.

3. 3

   Disconnect the wiring harness

   Disconnect the wiring harness from the sensor.

4. 4

   Remove the de-aeration cap

   Remove the engine coolant de-aeration cap to allow air to escape the coolant system during the draining process.

5. 5

   Drain the engine coolant

   Drain the engine coolant to a level below the sensor port to prevent spillage.

6. 6

   Remove the defective sensor

   Unthread and remove the defective coolant temperature sensor.

7. 7

   Install the new sensor

   Install the new OEM coolant temperature sensor.

8. 8

   Reconnect the wiring harness

   Reconnect the wiring harness.

9. 9

   Refill the engine coolant

   Refill the engine coolant. Note: If you are changing to or utilizing OAT (Organic Acid Technology) coolant, CNH service guidelines dictate that you must attach a specific label (CNH part number 47488993) to the system to indicate OAT coolant is in use.

10. 10

    Finalize repair

    Replace the de-aeration cap, reconnect the battery, and clear the fault codes.