Frequently Asked Question

Background

The EIS uses thermistor-type fluid temperature sensors for oil and water (coolant) temperatures. These sensors vary in resistance corresponding to changes in temperature. There are two types of sensors that might be used with the EIS. The type of sensor must match the type of instrument.

To determine the type of sensor the instrument requires:

The software version (SW Ver) of the EIS contains an “S”, “V” or “J” in the 3rd position that indicates the type of sensor it can use. For example, 44S84F would by an “S” type, where a 44V89F would be a “V” type.

To determine the sensor type:

The “S” type fluid temperature sensors will always have two wires coming from the body of the sensor, and will measure between 5000 and 15,000 ohms at room temperature.

The “V” or “J” type fluid temperature sensors are made by VDO. They have a round terminal on the top that a quick-disconnect slides over, and the case is used for ground. This sensor must be the VDO 300F/150C type (it is stamped onto one of the flats on the side of the sensor). This sensor has a resistance of between 800-1300 ohms at room temperature.

The EIS measures the resistance of the sensor via a 5-Volt excitation signal. This excitation is combined with the same pin that is used to sense the temperature.