16252 Mercury CAP, SLOW JET

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.
The ECM has been powered for at least two seconds.     The code is logged.
The value of the parameter is set to a gauge pressure of
500 kPa (75 psi).    
94-4 Fuel Delivery Pressure Sensor : Voltage Below Normal     The ECM detects signal voltage that is below normal.
The ECM has been powered for two seconds.    
96-8 Fuel Level Sensor : Abnormal Frequency, Pulse Width, or Period     The ECM detects signal voltage that is not changing at a normal rate for thirty seconds. Engine speed must be above 600 rpm.
The ECM has been powered for two seconds.     The code is logged.    
100-3 Engine Oil Pressure Sensor : Voltage Above Normal     The ECM detects signal voltage that is above normal.
The ECM has been powered for at least two seconds.     The code is logged.
The value of the parameter is set to a gauge pressure of
500 kPa (75 psi).    
100-4 Engine Oil Pressure Sensor : Voltage Below Normal     The ECM detects signal voltage that is below normal.
The ECM has been powered for two seconds.    
100-10 Engine Oil Pressure Sensor : Abnormal Rate of Change     The ECM detects signal voltage that is not changing at a normal rate for thirty seconds. Engine speed must be above 600 rpm.
The ECM has been powered for two seconds.    
290-3 Engine Cooling Fan Pump Pressure Sensor : Voltage Above Normal     The ECM detects signal voltage that is above normal.
The ECM has been powered for at least two seconds.     The code is logged.    
290-4 Engine Cooling Fan Pump Pressure Sensor : Voltage Below Normal     The ECM detects signal voltage that is below normal.
The ECM has been powered for two seconds.     The code is logged.    
274-3 Atmospheric Pressure Sensor : Voltage Above Normal     The ECM detects signal voltage that is above normal.
The ECM has been powered for at least two seconds.     The code is logged.
The value of the parameter is set to
100 kPa (14.5 psi).    
274-4 Atmospheric Pressure Sensor : Voltage Below Normal     The ECM detects signal voltage that is below normal.
The ECM has been powered for two seconds.    
1785-3 Intake Manifold Pressure Sensor : Voltage Above Normal     The ECM detects signal voltage that is above normal.
The ECM has been powered for at least two seconds.     The code is logged.
The value of the parameter is set to a gauge pressure of zero.
   
1785-4 Intake Manifold Pressure Sensor : Voltage Below Normal     The ECM detects signal voltage that is below normal.
The ECM has been powered for two seconds.    
1785-10 Intake Manifold Pressure Sensor : Abnormal Rate of Change     The ECM detects signal voltage that is not changing at a normal rate for thirty seconds. Engine speed must be above 1000 rpm.
The ECM has been powered for two seconds.    System OperationUse this procedure to troubleshoot any suspect problems with the following sensors:
Atmospheric pressure sensor
Engine oil pressure sensor
Fuel level sensor
Fuel pressure sensor
Intake manifold pressure sensorThe supply voltage is routed to terminal A of each sensor connector. The sensor return is routed to terminal B of each sensor connector. The sensor signal is routed to terminal C 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 sensor and 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 g01698314
Typical schematic
Illustration 2 g01698593
P1 ECM connector (P1-15) Air filter restriction
Illustration 3 g01698655
P2 ECM connector (P2-17) Sensor return (P2-28) Engine oil pressure sensor (P2-40) Fuel pressure sensor (P2-15) Intake manifold pressure sensor (P2-57) Atmospheric pressure sensor (P2-72) Sensor supply
Illustration 4 g01159881
Sensor connector (A) 5 V sensor supply (B) Sensor return (C) SignalTest Step 1. Check for "Active" or "Logged" Diagnostic Codes
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Turn the keyswitch to the START 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