0384476 JOHNSON DECAL SET

Table 1
Diagnostic Codes Table
Code Code Description Comments
100-3 Engine Oil Pressure Sensor Voltage Above Normal The ECM detects signal voltage that is above normal . The code is logged.
100-4 Engine Oil Pressure Sensor Voltage Below Normal The ECM detects signal voltage that is below normal . The code is logged.
274-3 Atmospheric Pressure Sensor Voltage Above Normal The ECM detects signal voltage that is above normal . The code is logged.
274-4 Atmospheric Pressure Sensor Voltage Below Normal The ECM detects signal voltage that is below normal . The code is logged.
460-3 Fuel Pressure Sensor - After Fuel Filter : Voltage Above Normal The ECM detects signal voltage that is above normal . The code is logged.
460-4 Fuel Pressure Sensor - After Fuel Filter : Voltage Below Normal The ECM detects signal voltage that is below normal . The code is logged.
1785-3 Intake Manifold Pressure Sensor Voltage Above Normal The ECM detects signal voltage that is above normal . The code is logged.
1785-4 Intake Manifold Pressure Sensor Voltage Below Normal The ECM detects signal voltage that is below normal . The code is logged.
2738-3 Turbocharger #1 Compressor Inlet Pressure Sensor : 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.
2738-4 Turbocharger #1 Compressor Inlet Pressure Sensor : 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. System OperationUse this procedure to troubleshoot any suspect problems with the following sensors:
Engine oil pressure sensor
Barometric pressure sensor
Fuel pressure sensor
Intake manifold pressure sensorThe supply voltage is routed to terminal 1 of each sensor connector. The sensor return is routed to terminal 2 of each sensor connector. The sensor signal is routed to terminal 3 of each sensor connector. The ECM provides short circuit protection for the internal power supply. A short circuit to the battery will not damage the internal power supply.The ECM performs an automatic calibration of these sensors whenever the ECM is powered and the engine is off for at least 5 seconds. During an automatic calibration, the ECM calibrates pressure sensors to the value of the atmospheric pressure at sea level. This calibration value is then checked against an acceptable offset pressure range.The 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 or a short in the signal circuit. When the ECM detects the presence of a voltage that is above the normal range of the sensor on the signal circuit, the ECM will generate an open circuit diagnostic code -3 for that sensor. When the ECM detects the absence of the pull-up voltage on the signal circuit, the ECM will generate a short circuit diagnostic code -4 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.
Illustration 1 g02164980
Schematic for the analog sensors
Illustration 2 g02164981
P2 ECM connector
(P2-15) Intake manifold pressure sensor
(P2-27) Fuel pressure sensor
(P2-28) Engine oil pressure sensor
(P2-30) Analog Return
(P2-72) Engine +5V supply
(P2-78) Barometric pressure sensor
(P2-81) Engine +5V supply
(P2-83) Analog Return
Illustration 3 g01422230
Sensor connector
(1) Analog sensor supply
(2) Analog sensor return
(3) Sensor signal
Table 2
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect Caterpillar Electronic Technician (ET) to the service tool connector.
B. Turn the keyswitch to the ON position.
C. Monitor the diagnostic codes on Cat ET. Check and record any diagnostic codes.
Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
D. 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 a terminal. The problem may be caused by moisture, corrosion, or wear.
E. Determine if the problem is active and related to one of the following diagnostic codes:
• -3
• -4
• -10
Codes
Result: A diagnostic code is not active.
The problem may be intermittent. If the problem is intermittent, refer to Troubleshooting, "Electrical Connectors - Inspect".
STOP
Result: A -10 diagnostic code is active.
Repair: A -10 diagnostic code indicates an open in the voltage supply to a sensor. If the code is only present for one sensor, the open will be between the sensor connector and a splice. If the open is for two or more sensors, the open will be before the splice for the voltage supply to those sensors. Repair the open in the