CM850 Electronic Control System – 019-019   Engine Coolant Temperature Sensor

Connect INSITE™ electronic service tool and verify the coolant temperature reading is the same on INSITE™ electronic service tool
as the gauge reading.

WARNING  Do not remove the pressure cap from a hot engine. Wait until the coolant temperature is below 50°C [120°F] before removing the pressure cap. Heated coolant spray or steam can cause personal injury.

WARNING  Coolant is toxic. Keep away from children and pets. If not reused, dispose of in accordance with local environmental regulations.

Drain the cooling system. Refer to Procedure 008-018 in the Troubleshooting and Repair Manual, ISC, QSC8.3, ISL and QSL9 Engines, Bulletin 4021418 or Troubleshooting Repair Manual, ISB^e, ISB, and QSB5.9 (Common Rail Fuel System), Bulletin 4021271.

Lift up on the locking tab and pull the electrical connectors apart.

Remove the sensor.

Inspect the engine harness connector and coolant temperature sensor for the following:

• cracked or broken connector shell
• missing or damaged connector seals
• dirt, debris, or moisture in or on the connector pins
• corroded, bent, broken, pushed back, or expanded pins.

Make sure the new sensor has an o-ring installed.

Lubricate the o-ring with clean engine oil.

Install the new sensor into the engine. Tighten the sensor.

Push the connectors together until they lock.

Fill the cooling system and operate the engine to check for leaks. Refer to Procedure 008-018 in the Troubleshooting and Repair Manual, ISC, QSC8.3, ISL and QSL9 Engines, Bulletin 4021418 or Troubleshooting Repair Manual, ISB^e, ISB, and QSB5.9 (Common Rail Fuel System), Bulletin 4021271.

Monitor the engine coolant temperature sensor with INSITE™ electronic service tool for proper operation.