Case IH ENG422 – ECM: Coolant Level Sensor Circuit Failure

The Engine Coolant Level Sensor is not functioning properly, or the jumper plug associated with it is missing. This fault code indicates an electrical malfunction, such as an open or short circuit in the sensor wiring, rather than a verified low coolant level. The sensor's role is to monitor the amount of coolant in the reservoir and alert the operator if the level drops below a safe threshold.

• 7100 series
• 8900 series
• 9100 series
• 7110
• 7120
• 7130
• 7140
• 7150
• 7210
• 7220
• 8910
• 8950
• 9110
• 9130
• Steiger models
• 1086
• 1486
• 1600 series
• 2100 series
• 2300 series
• 1660
• 1680
• 2166
• 2188
• 2366
• 2388
• 1800 series
• 2000 series
• CPX series
• CX series
• MX series
• CX80
• CX100
• MX100
• MX135
• MX170

1. 1

   Verify actual coolant level in the radiator and overflow reservoir to rule out a genuine low coolant condition

2. 2

   Visually inspect the sensor's wiring harness for chafing, breaks, or damage (especially the harness in front of the cab)

3. 3

   Unplug the sensor connector and check for corrosion (white or green deposits), bent pins, or loose wires. Clean any corrosion with electrical contact cleaner

4. 4

   Check the radiator cap (a faulty cap can prevent coolant from returning from the overflow tank) and ensure the radiator has a good ground connection

5. 5

   Perform a basic circuit test on single-wire sensors: disconnect the wire, observe the warning light, then touch the wire to a good chassis ground and observe if the light behaves in the opposite manner

6. 6

   Check for related faults, such as a failing oil pressure sender, which has been known to cause intermittent low coolant warnings, sometimes accompanied by a flickering temperature gauge or low voltage light

1. 1

   Safety First

   Park the machine on a level surface, shut down the engine, and allow the cooling system to cool completely to prevent burns.

2. 2

   Locate the Sensor

   The sensor is typically located in the top tank of the radiator, just below the filler neck.

3. 3

   Drain Coolant (If Necessary)

   Depending on its position, you may need to drain the coolant to a level below the sensor to avoid spillage during removal.

4. 4

   Remove the Old Sensor

   Disconnect the electrical connector. Using an appropriate wrench, unscrew the sensor from the radiator. The sensor typically has 1/8" NPT threads.

5. 5

   Install the New Sensor

   Apply a suitable thread sealant to the threads of the new sensor. Screw the new sensor into the radiator and tighten it securely, being careful not to overtighten.

6. 6

   Reconnect and Refill

   Reconnect the electrical connector. Refill the cooling system with the appropriate coolant to the correct level.

7. 7

   Test the System

   Start the engine and allow it to warm up, checking for leaks and verifying that the low coolant warning light is off.