0395339 JOHNSON WATER TUBE, Std.

Table 1
Diagnostic Codes Table    
Code and Description    Conditions which Generate this Code    System Response    
94-3 Fuel Delivery Pressure Sensor voltage above normal     The Electronic Control Module (ECM) detects signal voltage that is above normal for eight seconds.     The code is logged.
The value of the parameter is set to a gauge pressure of
600 kPa (87 psi).    
94-4 Fuel Delivery Pressure Sensor voltage below normal     The ECM detects signal voltage that is below normal for eight seconds.    
100-3 Engine Oil Pressure Sensor voltage above normal     The ECM detects signal voltage that is above normal for eight seconds.     The code is logged.
The value of the parameter is set to a gauge pressure of
600 kPa (87 psi).    
100-4 Engine Oil Pressure Sensor voltage below normal     The ECM detects signal voltage that is below normal for eight second.    
274-3 Atmospheric Pressure Sensor voltage above normal     The ECM detects signal voltage that is above normal for thirty seconds.     The code is logged.
The value of the parameter is set to a gauge pressure of
100 kPa (15 psi).    
274-4 Atmospheric Pressure Sensor voltage below normal     The ECM detects signal voltage that is below normal for thirty seconds.    
1785-3 Intake Manifold Pressure Sensor voltage above normal     The ECM detects signal voltage that is above normal for two seconds.     The code is logged.
The value of the parameter is set to a gauge pressure of
100 kPa (15 psi).    
1785-4 Intake Manifold Pressure Sensor voltage below normal     The ECM detects signal voltage that is below normal for two seconds.    System OperationUse this procedure to troubleshoot any suspect problems with the following sensors:
Fuel pressure sensor
Engine oil pressure sensor
Atmospheric 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 five 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 g02498403
Schematic for the analog sensors
Illustration 2 g02495016
Sensor locations for the analog sensors (1) Intake manifold pressure sensor (2) Fuel pressure sensor (3) Atmospheric pressure sensor (4) Engine oil pressure sensor (5) J2/P2 ECM connectors
Illustration 3 g01422228
P2 ECM connector (P2-15) Intake manifold pressure sensor (P2-17) Analog sensor return (P2-28) Engine oil pressure sensor (P2-40) Fuel pressure sensor (P2-57) Atmospheric pressure sensor (P2-72) Analog sensor supply
Illustration 4 g01422230
Sensor connector (1) Analog sensor supply (2) Analog sensor return (3) Sensor signalTest Step 1. Check for "Active" and "Logged" Diagnostic Codes
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Turn the keyswitch to the ON position.
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.
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.
Determine if the problem is active and related to one of the following diagnostic codes:
-3
-4
-10Expected Result:A diagnostic code is not active.Results:
OK - A diagnostic code is not active.Repair: The problem may be intermittent. If the problem is intermittent, refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - 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 wiring or connectors. Refer to the electrical schematic for the locations of splices in the harness. Refer to Troubleshooting, "Sensor Supply - Test" for information that is related to troubleshooting the sensor supply.STOP
Not OK - A -3 code or a -4 code is active. Proceed to Test Step 2.Test Step 2. Check the 5 V Supply Voltage at the Sensor Connector
Do not disconnect the suspect connector.
Connect a multimeter between pin 1 and pin 2 on the sensor side of the connector for the suspect sensor.
Measure the voltage between pin 1 and pin 2 for the suspect sensors.
Wiggle the harness while you monitor the voltage on the voltmeter. Perform the 45 N (10 lb) pull test on each wire in the circuit. Each terminal and each connector should easily withstand 45 N (10 lb) of tension and each wire should remain in the connector body. This test checks whether the wire was properly crimped in the terminal and whether the terminal was properly inserted into the connector.Expected Result:The supply