Genuine BMW 335i Coolant Temperature Sensor

BMW 335i Coolant Temperature Sensor Parts Questions & Experts Answers

• Temperature Sensor Water/Oil
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  Q:

  What is the function and installation process of the coolant temperature sensor in the N54 six cylinder engine on BMW 335i?

  Posted by Rodney N.

  A:

  A common sensor is the engine coolant temperature (ECT), which is an NTC sensor, in which resistance opposes the temperature variation of the coolant. There is no reference current; it takes a 5-volt reference voltage, and any variation in the voltage drop across the sensor corresponds to coolant temperature changes. Where the ECT sensor input is either bad or unrealistic, the MIL turns on whenever OBD II fault thresholds are reached; the ECM replaces 80°C (176°F) as a minimum for engine running; ignition timing is set to a baseline maximum. The ECT sensor is located factor to the cylinder head below the throttle body. It is to be taken off by putting the rubber line in position and unscrewing the fastener using a screwdriver, while being ready to collect dripping fluids if the engine is still hot. Once the electrical connector is removed, you have to remove a couple of bolts to pull off the ECT sensor from the cylinder head; some coolant will drip, so be prepared. For removal, unscrew from the engine block and unbolt from the coolant line, while for installation reverse the process and add new copper sealing washer for the sensor, check and replace if necessary the O-rings on the coolant line and refill the lost coolant. Last of all look for any fault code and clear any that might have been stored in the ECM memory after replacement.

  Answered by BMW Parts Specialist Chaz / Jul 29, 2023