C15 and C18 Engines for Caterpillar Built Machines Caterpillar

During normal operation, each pressure sensor outputs a signal voltage that accurately represents the pressure that is sensed by the sensor. However, certain circuit conditions can cause a signal voltage to become inaccurate.

During each key on event of at least two seconds, the Electronic Control Module (ECM) evaluates the signal voltage from each pressure sensor. The ECM compares each signal voltage to a reference voltage. The reference voltage that is used depends on the sensor.

If a signal voltage is close to the reference voltage, the ECM will internally adjust the signal voltage. The internal adjustment causes the pressure value for the sensor to be correct. This process is called automatic sensor calibration.

If a signal voltage is not close to the reference voltage, the ECM will not internally adjust the signal voltage. The ECM will set a fault code that indicates there is a problem with the signal voltage.

Table 1 indicates the maximum error that is permitted for each sensor, and the reference for that sensor. Refer to the troubleshooting procedure to determine the root cause of the incorrect signal voltage.

Table 1

Diagnostic Trouble Codes
CDL Code	J1939 Code	Code Description (code descriptions may vary)	Comments
100-13	100-13	Engine Oil Pressure Sensor : Out of Calibration	During key on, the signal voltage from the engine oil pressure sensor indicated an engine oil pressure greater than +/- 54 kPa (8 psi) from the atmospheric pressure sensor. Reference sensor : Atmospheric Pressure Sensor
274-13	108-13	Atmospheric Pressure Sensor : Out of Calibration	During key on, the signal voltage from the atmospheric pressure sensor indicated an atmospheric pressure other than 0 kPa (0 psi). This sensor is used as a reference sensor
460-13	411-13	Fuel Pressure Sensor - After Fuel Filter : Out of Calibration	During key on, the signal voltage from the fuel outlet pressure sensor (after secondary fuel filter) indicated a pressure other than 0 kPa (0 psi) . This sensor is used as a reference sensor
1785-13	3251-13	Intake Manifold Pressure Sensor : Out of Calibration	During key on, the signal voltage from the Intake Manifold pressure sensor indicated an Intake Manifold pressure greater than +/- 18 kPa (3 psi) from the Atmospheric Pressure sensor. Reference sensor : Atmospheric Pressure Sensor

Table 2

Troubleshooting Test Steps	Values	Results
1. Check for Diagnostic Trouble Codes The engine coolant temperature must be greater than 0° C (32° F) before beginning this procedure. A. Establish communication between Caterpillar Electronic Technician (ET) and the Electronic Control Module (ECM) . Refer to Troubleshooting, "Electronic Service Tools", if necessary. B. Download the "Warranty Report" from the engine ECM before performing any troubleshooting or clearing diagnostic trouble codes. C. Wait at least 30 seconds in order for the diagnostic codes to become active. Look for an active -13 code or for a logged -13 code.	Diagnostic Trouble Codes	Result: There is an active or there is a logged -13 code. Proceed to Test Step 2.
2. Check for Debris A. Turn the keyswitch to the OFF position. B. Check the suspect sensor for debris. C. If applicable, check the reference sensor for debris. D. Check the sensor measurement port for blockage by debris. E. If debris is found, clear the debris from the measurement port and replace the suspect sensor. F. Turn the keyswitch to the ON position. G. Check for -13 codes. Wait at least 30 seconds in order for the diagnostic codes to become active.	Debris	Result: The sensor measurement port is not blocked by debris. Proceed to Test Step 3. Result: A -13 code is not present, return the unit to service. Result: A -13 code is present, replace the suspect sensor. Verify that the problem is resolved. Result: If only a 460-13 or 411-13 code is present, replace the reference sensor. Verify that the problem is resolved. Result: If more than one -13 code is present and the codes have a reference sensor, replace the reference sensor. Verify that the problem is resolved.
3. Inspect the Suspect Sensor Connector A. Turn the keyswitch to the OFF position. Inspect the suspect sensor connector for moisture and/or corrosion.	Moisture	Result: The suspect sensor connector has moisture and/or corrosion. Proceed to Test Step 4. Result: The suspect sensor connector does not have moisture and/or corrosion. Proceed to Test Step 5.
4. Remove any moisture and/or corrosion A. Disconnect the suspect sensor connector. B. Remove any moisture and/or corrosion from the outside of the connector. Check for moisture and corrosion inside the connector. Verify that the seals for the wires are sealing correctly. Refer to Troubleshooting, "Electrical Connectors - Inspect", if necessary. C. If necessary, repair the connector or replace the connector. D. Reconnect the connector. Verify that the connection is secure. E. Turn the keyswitch to the ON position. F. Monitor the diagnostic codes on Cat ET. Check for -13 codes. Wait at least 30 seconds in order for the diagnostic codes to become active.	Moisture	Result: A -13 code is not present, return the unit to service. Result: A -13 code is present, replace the suspect sensor. Verify that the problem is resolved. Result: If only a 460-13 or 411-13 code is present, replace the reference sensor. Verify that the problem is resolved. Result: If more than one -13 code is present and the codes have a reference sensor, replace the reference sensor. Verify that the problem is resolved.
5. Check for Moisture and/or Corrosion in the Circuit A. Check all of the connectors in the circuit for moisture and/or corrosion. B. Check for corrosion inside the connector. Verify that the seals for the wires are sealing correctly. Refer to Troubleshooting, "Electrical Connectors - Inspect", if necessary. C. If necessary, repair the connector or replace the connector. D. Reconnect the connector. Verify that the connection is secure. E. Turn the keyswitch to the ON position. F. Monitor the diagnostic codes on Cat ET. Check for -13 codes. Wait at least 30 seconds in order for the diagnostic codes to become active.	Moisture	Result: A -13 code is not present, return the unit to service. Result: A -13 code is present, replace the suspect sensor. Verify that the problem is resolved. Result: If only a 460-13 or 411-13 code is present, replace the reference sensor. Verify that the problem is resolved. Result: If more than one -13 code is present and the codes have a reference sensor, replace the reference sensor. Verify that the problem is resolved.

Complete the procedure in the order in which the steps are listed.

If the procedure corrected the issue, return the engine to service.

If the procedure did not correct the issue, Contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).