CUP 6S2826 - Caterpillar

System Operation Description:Use this procedure to troubleshoot any suspect problems with the following sensors:
94-03 Filtered Fuel Pressure open/short to +batt
94-04 Filtered Fuel Pressure short to ground
101-03 Crankcase Pressure open/short to +batt
101-04 Crankcase Pressure short to ground
110-03 Engine Coolant Temperature open/short to +batt
110-04 Engine Coolant Temperature short to ground
105-03 Inlet Manifold Air Temperature open/short to +batt
105-04 Inlet Manifold Air Temperature short to ground
1175-03 Engine Oil Temperature open/short to +batt
175-04 Engine Oil Temperature short to ground
273-03 Turbo Outlet Pressure open/short to +batt
273-04 Turbo Outlet Pressure short to ground
274-03 Atmospheric Pressure open/short to +batt
274-04 Atmospheric Pressure short to ground
275-03 Right Turbo Inlet Pressure open/short to +batt
275-04 Right Turbo Inlet Pressure short to ground
275-03 Left Turbo Inlet Pressure open/short to +batt
275-04 Left Turbo Inlet Pressure short to ground
279-03 Aftercooler Temperature open/short to +batt
279-04 Aftercooler Temperature short to ground
542-03 Unfiltered Engine Oil Pressure open/short to +batt
542-04 Unfiltered Engine Oil Pressure short to ground
543-03 Filtered Oil Pressure Sensor open/short to +batt
543-04 Filtered Oil Pressure Sensor short to ground
827-08 Left Exhaust Temperature signal abnormal
828-08 Right Exhaust Temperature signal abnormalEngine sensors provide various signals to the engine's Electronic Control Module (ECM). These sensors receive a regulated voltage from the ECM. Analog sensors receive 5.0 0.2 VDC and digital sensors receive 8.0 0.4 VDC.The ECM performs an automatic calibration of these sensors whenever the ECM is powered and the engine is off for at least five seconds. During an automatic calibration, the ECM calibrates pressure sensors to the value of the atmospheric pressure sensor and against an acceptable offset pressure range.Pull-up VoltageThe ECM continuously outputs a pull-up voltage on the input terminal from an analog sensor. The ECM uses this pull-up voltage in order to detect an open in the signal circuit. When the ECM detects the presence of a voltage that is above a threshold on the signal circuit, the ECM will generate an open circuit diagnostic code 0-3 for that sensor. The presence of pull-up voltage at the sensor connector indicates that the wires from the sensor connector to the ECM are not open or shorted to ground.Note: No pull-up voltage is present on the input from a digital sensor.
Illustration 1 g01168791Test Step 1. Check for "Active" or "Logged" Diagnostic Codes
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Turn the engine control to the STOP mode.
Turn the engine battery disconnect switch to the ON position.
Monitor the diagnostic codes on Cat ET. Check and record any diagnostic codes. Note: Wait at least 15 seconds in order for the diagnostic codes to become active.
Determine if a diagnostic code has occurred several times. Note: A diagnostic code that is logged several times is an indication of an intermittent problem. Most intermittent problems are the result of a bad connection between a socket and a pin in a connector or a bad connection between a wire and terminal.
Determine if the problem is active and related to one of the following diagnostic codes:
03
04
08Expected Result:A diagnostic code has occurred several times.Results:
OK - A diagnostic code has occurred several times.