C175-16 Locomotive Engine Caterpillar

Sensor Calibration Required - Test

Usage:

Use this procedure to troubleshoot a problem with pressure sensor out of calibration. Also, use this procedure if one of the following diagnostic codes is active or easily repeated.

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.

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Table 1
J1939 Code and Description	CDL Code and Description	Comments
101-13 Crankcase Air Pressure Sensor : Out of Calibration	101-13 Crankcase Air Pressure Sensor : Out of Calibration	During key on, the signal voltage from the crankcase air pressure sensor indicated a crankcase air pressure greater than +/- 1.5 kPa (0.2 psi). There is not a reference sensor for this sensor
3563-13 Engine Intake Manifold #1 Absolute Pressure : Out of Calibration	1785-13 Intake Manifold Pressure Sensor : Out of Calibration	During key on, the signal voltage from the crankcase air pressure sensor indicated a crankcase air pressure greater than +/- 18 kPa (3 psi). Reference sensor: Atmospheric Pressure Sensor

Probable Causes

Codes
Debris
Moisture

Recommended Actions

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Table 2
Troubleshooting Test Steps	Values	Results
1. Check for Codes Note: The engine coolant temperature must be greater than 0° C (32° F) before beginning this procedure. A. Connect Cat^® Electronic Technician (ET) to the service tool connector. B. Look for active codes that are associated with the system for the event code.	Codes	Result: An associated code is active. Repair: Troubleshoot any associated codes before continuing with this test. Result: A code is active or logged. Proceed to Test Step 2.
2. Check for Debris A. Remove electrical power from the engine. B. Check the 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 sensor. F. Connect Cat ET. G. Use Cat ET to monitor the following code: - -13	Debris	Result: The sensor measurement port is not blocked by debris. Proceed to Test Step 3. Result: A -13 code is not active. Return to service. Result: A -13 code is active. Repair: Replace the sensor. If more than one -13 code is active and the codes have a reference sensor, replace the reference sensor. If the problem is not resolved, proceed to Test Step 3.
3. Inspect the Sensor Connector A. Remove electrical power from the engine. B. Inspect the sensor connector for moisture and corrosion.	Moisture	Result: The sensor connector does not have moisture or corrosion. Proceed to Test Step 5. Result: The sensor connector has moisture and/or corrosion. Proceed to Test Step 4.
4. Remove any moisture and/or corrosion A. Remove electrical power from the engine. B. Disconnect the sensor connector. C. 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" for additional information. D. If necessary, repair or replace the connector. E. Reconnect the connector. Verify that the connection is secure. F. Connect Cat ET. G. Use Cat ET to monitor the following code: - -13	Moisture	Result: A -13 code is not active. Return the service. Result: A -13 code is active. Repair: Replace the sensor. If more than one -13 code is active and the codes have a reference sensor, replace the reference sensor. If the problem is not resolved, proceed to Test Step 5.
5. Check for Moisture and/or Corrosion in the Circuit A. Remove electrical power from the engine. B. Check all of the connectors in the circuit for moisture and/or corrosion. C. Check for corrosion inside the connector. Verify that the seals for the wires are sealing correctly. Refer to Troubleshooting, "Electrical Connectors - Inspect" for additional information. D. If necessary, repair or replace the connector. E. Reconnect the connector. Verify that the connection is secure. F. Connect Cat ET. G. Use Cat ET to monitor the following code: - -13	Moisture	Result: A -13 code is not active. Return the service. Result: A -13 code is active. Repair: Replace the sensor. If more than one -13 code is active and the codes have a reference sensor, replace the reference sensor. Verify that the repair eliminated the problem.

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).