SEAL 2M7876 - Caterpillar

Use this procedure to troubleshoot the electrical system if a problem is suspected with the sensors or if any one of the diagnostic codes in Table 1 is active or easily repeated.
Table 1
Diagnostic Codes Table
J1939 Codes CDL Codes Code Description System Response
100-3 100-3 Engine Oil Pressure : Voltage Above Normal The code is logged.
If the signal is valid, the parameter will use the value from the sensor for the unfiltered oil pressure.
If the signal is not valid, the value of the parameter will be set to 600 kPa (87 psi).
100-4 100-4 Engine Oil Pressure : Voltage Below Normal
101-3 101-3 Engine Crankcase Pressure : Voltage Above Normal The code is logged.
The value of the parameter will be set to the value from the barometric pressure sensor.
101-4 101-4 Engine Crankcase Pressure : Voltage Below Normal
108-3 274-3 Barometric Pressure : Voltage Above Normal The code is logged.
The value of the parameter will be set to the value from a map-dependent value that is stored in the ECM.
108-4 274-4 Barometric Pressure : Voltage Below Normal
3563-3 1785-3 Engine Intake Manifold #1 Absolute Pressure : Voltage Above Normal The ECM detects signal voltage that is not in the acceptable range.
The code is logged.
The value of the parameter is set to a gauge pressure.
3563-4 1785-4 Engine Intake Manifold #1 Absolute Pressure : Voltage Below Normal
5578-3 289-3 Engine Fuel Delivery Absolute Pressure : Voltage Above Normal The ECM detects signal voltage that is not in the acceptable range.
The code is logged.
The value of the parameter is set to a gauge pressure.
5578-4 289-4 Engine Fuel Delivery Absolute Pressure : Voltage Below Normal
5580-3 460-3 Engine Fuel Delivery Absolute Pressure : Voltage Below Normal The ECM detects signal voltage that is not in the acceptable range.
The code is logged.
The value of the parameter is set to a gauge pressure.
5580-4 460-4 Engine Filtered Fuel Delivery Absolute Pressure : Voltage Below Normal System OperationUse this procedure to troubleshoot any suspect problems with the following sensors:
Atmospheric pressure sensor
Crankcase pressure sensor
Engine coolant pump outlet pressure sensor
Intake manifold pressure sensor
Unfiltered fuel pressure sensorBackground InformationThe ECM continuously creates a pull-up voltage on the signal wire for each sensor. The ECM uses this pull-up voltage in order to detect a problem in the signal circuit. When the ECM detects voltage that is above a threshold on the signal wire, the ECM activates a high voltage -3 diagnostic code. When the ECM detects voltage that is below a threshold on the signal wire, the ECM activates a low voltage -4 diagnostic code.Note: There may be a delay of 30 seconds or more in order for Caterpillar Electronic Technician (ET) to display an active diagnostic code. When you check for a diagnostic code, be sure to wait at least 30 seconds.The following components can cause these codes:
Electrical connector or wiring
Sensor
ECMThe most likely cause of a code is a problem with an electrical connector or wiring. The least likely cause of a code is the ECM.
Illustration 1 g03661084
Schematic for the analog sensors
Table 2
Troubleshooting Test