Usage:
784B (5RK) Tractor;
785B (6HK),
789B (7EK),
793B (1HL),
793C (4AR) Trucks
The 100-3055 Pulse Width Modulated Temperature Sensor Group has electronic components that are affected by heat from various sources. Most causes of over temperature related problems result from exhaust leaks. Look for exhaust leaks or sooting on the sensor for indication of failure cause.
Another area of possible sensor failure relates to the need for proper training for operators. Excessive brake heat can cause the same failure symptoms.
As the temperature of the sensor circuitry exceeds 250 degrees F., the devices become less stable. Temperatures in excess of 270 to 280 degrees F. may cause the device to quit fuctioning, and VIMS will report CID/FMI codes indicating sensor failure.
Usually when the temperature of the sensor is lowered, the sensor will start reporting correct temperatures.
Study of returned parts show that many of the sensors have no damage. When temperatures return to a normal operating range and the CID/FMI codes still show sensor failure, perform on-machine troubleshooting procedures and replace sensor if test procedures indicate failure.