CUTTING EDGE 2.50 cm(.984 in.) 8J8118 - 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
J1939 Code and Description Comments
1208-13
Engine Pre-filter Oil Pressure : Out of Calibration During the last calibration attempt, a problem has been detected.
The code is logged.
During a manual calibration, the pressure offset value is set to 0 kPa (0 psi).
During an automatic calibration, the pressure offset value is set to the previous calibration value.
2452-13
Generator Total Real Power : Out of Calibration The diagnostic will be active when using a secondary generator power sensor and the values between the PWM and analog signal differ by more than 100 kW.
4817-13
Engine Intake Manifold #1 Absolute Pressure : Out of Calibration During key on, the signal voltage from the Intake Manifold pressure sensor indicated an Intake Manifold pressure greater than +/- 15 kPa (2.2 psi) from the Atmospheric Pressure sensor.
Reference sensor : Atmospheric Pressure Sensor
5631-13
Engine Throttle Valve Differential Pressure : Out of Calibration During Key on, the signal voltage from the engine throttle valve differential pressure sensor indicated that the differential pressure detected is greater than 11 kPa (1.6 psi)
There is not a reference for this sensor.
Table 2
Troubleshooting Test Steps Values Results
1. Check for Diagnostic Trouble Codes
A. Establish communication between Cat® 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 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