how to fix P0118 coolant temperature code in BMW 3 Series F30/F31 (2012-2019)

BMW 3 Series F30/F31 (2012-2019)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

Error Code: P0118

3 min read

593 words

Problem Statement

The P0118 code indicates a high-temperature reading from the coolant temperature sensor in a BMW 3 Series F30/F31 (2012-2019), which may lead to improper engine management and pot

Error Code

P0118

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical systems.
•Allow the engine to cool completely before opening the cooling system.

Symptoms

•Check engine light illuminated
•Engine overheating
•Poor fuel economy
•Erratic temperature gauge readings
•Engine stalling or rough idle
•Increased emissions

Diagnostic Steps

1
Scan the vehicle's computer using an OBD-II scanner to confirm the P0118 code and check for any related codes.
2
Inspect the coolant level and ensure it is at the proper level; top off if necessary.
3
Visually inspect the coolant temperature sensor and wiring for any signs of damage, corrosion, or loose connections.
4
Measure the resistance of the coolant temperature sensor using a multimeter at different temperature points to verify its functionality.
5
Check the engine coolant for contamination or air pockets that may affect temperature readings.
6
Inspect the thermostat for proper operation, ensuring it opens and closes at the correct temperatures.

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

✓Test the affected component to ensure it functions correctly
✓Check for any error codes or warning lights
✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

•Follow the manufacturer's recommended maintenance schedule
•Address warning signs early before they develop into major issues
•Use quality parts and fluids recommended for your vehicle
•Keep detailed records of all repairs and maintenance

Tools & Equipment Required

•OBD-II scanner
•Multimeter
•Socket set
•Torque wrench
•Drain pan
•Screwdrivers

Parts Required

•New coolant temperature sensor
•New thermostat (if necessary)
•Coolant (as specified in the owner's manual)

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Diagnostic Steps

1
Scan the vehicle's computer using an OBD-II scanner to confirm the P0118 code and check for any related codes.
2
Inspect the coolant level and ensure it is at the proper level; top off if necessary.
3
Visually inspect the coolant temperature sensor and wiring for any signs of damage, corrosion, or loose connections.
4
Measure the resistance of the coolant temperature sensor using a multimeter at different temperature points to verify its functionality.
5
Check the engine coolant for contamination or air pockets that may affect temperature readings.
6
Inspect the thermostat for proper operation, ensuring it opens and closes at the correct temperatures.

Solution

1. Preparation

Gather necessary tools and parts.
Disconnect the negative battery terminal to prevent electrical shorts.
Allow the engine to cool completely before starting work.

2. Replace Coolant Temperature Sensor

Locate the Sensor: Identify the coolant temperature sensor, typically found near the thermostat housing.
Remove Electrical Connector: Gently pull off the electrical connector from the sensor.
Drain Coolant: Place a drain pan under the radiator, open the drain plug, and drain a sufficient amount of coolant to prevent spills when removing the sensor.
Remove the Sensor: Use a socket or wrench to unscrew the coolant temperature sensor from its housing.
Install New Sensor: Apply a small amount of thread sealant to the new sensor and install it in the housing, tightening to the manufacturer’s specified torque (usually around 20 Nm).
Reconnect Electrical Connector: Plug the electrical connector back onto the new sensor.
Refill Coolant: Refill the cooling system with the appropriate coolant mixture (consult the owner’s manual for specifications).
Bleed the Cooling System: Follow the manufacturer’s procedure to bleed the cooling system of any air pockets.

3. Check Thermostat

Remove Thermostat: If previously inspected and found faulty, remove the thermostat from its housing by unscrewing the bolts.
Inspect/Replace: Check the thermostat for proper operation (it should open in hot water) and replace if necessary.
Reinstall Thermostat: Reinstall the thermostat, ensuring the gasket is in good condition, and torque the bolts to the manufacturer’s specifications.