The engine's primary Electronic Control Module (ECM) attempts to perform an automatic calibration of all pressure sensors whenever the ECM is powered and the engine is OFF for at least five seconds. Cranking the engine during the first five seconds causes the ECM to abort the calibration attempt. A manual calibration should be performed if a pressure sensor is replaced.
During an automatic pressure sensor calibration, the ECM checks all pressure sensors against an acceptable range. If any pressure sensor reading is outside the acceptable range, the previous calibration value is used. The ECM then calibrates all pressure sensors against the atmospheric pressure sensor.
A pressure sensor calibration will not be successful if there are active diagnostic codes with an FMI of 03 and/or 04.
Note: The Engine Control Switch (ECS) is mounted within an instrument panel that is located on the right side of the engine. The ECS is locked into the AUTO position with a pin. The pin must be removed in order to perform this test. After performing this test, ensure that the ECS is placed in the AUTO position and that the locking pin has been reinstalled.
Test Step 1. Check for "ACTIVE" Diagnostic Codes.
- Turn the ECS to the OFF/RESET position.
- Connect the Caterpillar Electronic Technician (ET) to the service tool connector.
- Turn the ECS to the ON position. The engine should be OFF.
- Check for active diagnostic codes.
Expected Result:
There should be no active diagnostic codes.
Results:
- OK - There are no active diagnostic codes. Proceed to test step 2.
- Not OK - A pressure sensor with an active diagnostic code cannot be calibrated.
Repair: Perform the appropriate troubleshooting procedure.
Stop.
Test Step 2. Perform a Manual Calibration of the Sensors.
- Select the calibration screen on the Cat ET. The ECM will perform a manual pressure sensor calibration when this screen is entered.
Expected Result:
The Cat ET screen indicates that the calibration was completed.
Results:
- OK - The Cat ET screen indicates that the calibration was completed.
Repair: Reset the system and check for any active diagnostic codes.
Stop.
- Not OK - All pressure sensors could not be calibrated. Proceed to test step 3.
Test Step 3. Determine the Cause of Failed Manual Calibration.
- Check if any pressure sensors have an active diagnostic code. A pressure sensor calibration will not be successful if there are active diagnostic codes with an FMI of 03 and/or 04.
- Verify that the correct sensor has been installed.
- Check the display status screen on the Cat ET for the pressure sensor reading.
- Turn the ECS to the OFF/RESET position.
Expected Result:
The ECM should read crankcase pressure as 8 kPa (1.1 psi) from the atmospheric pressure reading. The ECM should read turbocharger compressor inlet pressure as 8 kPa (1.1 psi) from the atmospheric pressure reading. The ECM should read oil pressure as 27 kPa (4 psi) from the atmospheric pressure. The ECM should read turbocharger compressor outlet pressure as 15 kPa (2 psi) from the atmospheric pressure. The atmospheric pressure reading should be steady. The atmospheric pressure in your area will be displayed from 5 kPa (0.7 psi). The atmospheric pressure must be greater than 111 kPa (16 psi) for a successful calibration.
Results:
- OK - Repeat manual calibration of the sensors.
Repair: Verify that no active diagnostic codes are present. Repeat the manual calibration.
Stop.
- Not OK - There is a problem with the wiring harness and/or the sensor. Inspect the components for damage, corrosion or abrasion. Repair the components and/or replace the components.
Repair: Perform the appropriate troubleshooting procedure.
Stop.