804175 Mercury MAIN JET, #128

Table 1
Diagnostic Trouble Codes    
Code and Description    Conditions that Generate the Code    System Response    
52-3
Engine Intercooler Temperature : Voltage Above Normal     The ECM detects signal voltage that is greater than 4.95 VDC for 8 seconds.     The code is logged.
The value of the parameter is set to a default value.    
52-4
Engine Intercooler Temperature : Voltage Below Normal     The ECM detects signal voltage that is less than 0.2 VDC for 8 seconds.    
110-3
Engine Coolant Temperature : Voltage Above Normal     The ECM detects signal voltage that is greater than 4.95 VDC for 8 seconds.     The code is logged.
The value of the parameter is set to a default value.    
110-4
Engine Coolant Temperature : Voltage Below Normal     The ECM detects signal voltage that is less than 0.2 VDC for 8 seconds.    
172-3
Intake Manifold Air Temperature Sensor : Voltage Above Normal     The ECM detects signal voltage that is greater than 4.95 VDC for 8 seconds.     The code is logged.
The value of the parameter is set to a default value.    
172-4
Intake Manifold Air Temperature Sensor : Voltage Below Normal     The ECM detects signal voltage that is less than 0.2 VDC for 8 seconds.    
3563-3
Engine Intake Manifold 1 Temperature : Voltage Above Normal     The ECM detects signal voltage that is greater than 4.95 VDC for 8 seconds.     The code is logged.
Ambient temperature must be greater than -35 °C (-31 °F) to log this diagnostic code.
The value of the parameter is set to a default value.    
3563-4
Engine Intake Manifold 1 Temperature : Voltage Below Normal     The ECM detects signal voltage that is less than 0.2 VDC for 8 seconds.     The code is logged.
Ambient temperature must be less than
140 °C (284 °F) to log this diagnostic code.
The value of the parameter is set to a default value.    System OperationUse this procedure to troubleshoot any suspect problems with the following sensors for the primary ECM:
Coolant temperature sensor
Intake manifold air temperature sensor
Aftercooler temperature sensor
Illustration 1 g03366373
Typical schematic
Illustration 2 g03241162
Terminal locations at the P1 ECM connector (prim.) for the passive sensors (P1-16) Aftercooler temp front (P1-17) Aftercooler temp rear
Illustration 3 g03246317
Terminal locations at the P2 ECM connector (prim. & sec.) for the passive sensors (P2-30) Return (P2-63) Return (P2-84) Coolant temperature (P2-93) Return (P2-95) Intake manifold air temperature
Illustration 4 g01155187
Terminal locations at the connector for the passive analog sensors (Terminal 1) Sensor signal (Terminal 2) Sensor return
Table 2
Troubleshooting Test Steps    Values    Results    
1. Check for "Active" or "Logged" Diagnostic Codes
A. Connect Caterpillar Electronic Technician (ET) to the service tool connector.
B. Restore the electrical power to the ECM.
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 the problem is active and related to one of the following diagnostic codes:
-3
-4
   
Codes    
Results: No diagnostic codes are active at this time.
Repair: The problem may be intermittent. If the problem is intermittent refer to Troubleshooting, "Electrical Connectors - Inspect"
Results: An active -3 diagnostic code is present.
Proceed to Test Step 2
Results: An active -4 diagnostic code is present.
Proceed to Test Step 4
   
2. Check for a Short to the +Battery at the Sensor Connector
A. Measure the voltage on the harness side of the sensor connector between pin 1 and pin 2 for the suspect sensor.
   
+Battery    
Results: The supply voltage is less than Battery voltage.
Proceed to Test Step 3
Results: The supply voltage is equal to Battery voltage.
Repair: There is a short in the harness to the +Battery. Repair the wiring.
Verify that the repair eliminated the problem.
   
3. Create a Short at the Sensor Connector
A. Turn the main disconnect switch to the OFF position.
B. Disconnect the suspect sensor.
C. Use a wire jumper in order to create a short between terminal 1 (signal) and terminal 2 (sensor return) at the sensor connector.
D. Restore the electrical power to the ECM.
E. Access the "Active Diagnostic Code" screen on Cat ET. Check for an active -4 diagnostic code for the suspect sensor.
Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
F. Turn the main disconnect switch to the OFF position.
   
Short    
Results: A -3 diagnostic code was active before creating the short at the sensor connector. A -4 diagnostic code became active after creating the short at the sensor connector.
Repair: Temporarily connect a new sensor to the harness, but do not install the new sensor in the engine. Verify that there are no active diagnostic codes for the sensor. If there are no active diagnostic codes for the sensor, permanently install the new sensor. Clear any logged diagnostic codes.
Verify that the repair eliminated the problem.
Results: A -3 diagnostic code is still active for the suspect sensor.
Proceed to Test Step 5
   
4. Create an Open at the Suspect Sensor Connector
A. Disconnect the sensor connector of the suspect sensor with the active -4 diagnostic code.
B. Restore the electrical power to the ECM.
C. Access the "Active Diagnostic Code" screen on Cat ET. Check for an active -3 diagnostic code.
Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
D. Turn the main disconnect switch to the OFF position.
   
Open    
Results: A -4 diagnostic code was active before disconnecting the sensor. A -3 diagnostic code became active af