PIN 5J5365 - Caterpillar

Use this procedure to troubleshoot the electrical system if a problem is suspected with the cooling fan speed sensor. Also use this procedure if the diagnostic code in Table 1 is active or easily repeated.Clear all "Active" codes using Cat ET before proceeding with the following procedure. Refer to Troubleshooting, "Diagnostic Capabilities - Clearing Active Codes for On Board Diagnostics (OBD)" for more information on clearing "Active" codes.
Table 1
Diagnostic Codes Table    
J1939 Code     CDL Code     Code Description     Comments    
N/A     E1363 (1)     Low Engine Cooling Fan Speed     The code is logged.    
N/A     544-2     Engine Cooling Fan Speed Sensor : Erratic, Intermittent, or Incorrect     The code is logged.    
N/A     544-8     Engine Cooling Fan Speed Sensor : Abnormal Frequency, Pulse Width, or Period     The code is logged.    The engine cooling fan speed sensor provides a signal to the Electronic Control Module (ECM). The ECM controls fan speed by varying the current to the fan control solenoid.The engine cooling fan speed sensor receives a supply voltage of 8.0 0.5 VDC from the ECM. The sensor outputs a frequency that is directly proportional to fan speed. The sensor generates a signal pulse for each revolution of the fan. The output frequency varies between 5 Hz to 180 Hz over the speed range between 50 rpm and 1800 rpm.
Illustration 1 g03011039
Schematic for the fan speed sensor
Table 2
Troubleshooting Test Steps     Values     Results    
1. Check the Status of the Engine Fan Speed
A. Turn the keyswitch