878365T00 Mercury POWERHEAD ASSEMBLY

Table 1
Diagnostic Codes Table    
Description    Conditions which Generate this Code    System Response    
827-8 Left Exhaust Temperature Sensor : Abnormal Frequency, Pulse Width, or Period     The Electronic Control Module (ECM) detects a sensor frequency that is greater than 1000 Hz or less than 150 Hz.
The ECM detects a duty cycle that is greater than 90 percent or a duty cycle that is less than 10 percent.     The value of the parameter is set to zero.
The code is logged.    
828-8 Right Exhaust Temperature Sensor : Abnormal Frequency, Pulse Width, or Period     The ECM detects a sensor frequency that is greater than 1000 Hz or less than 150 Hz.
The ECM detects a duty cycle that is greater than 90 percent or a duty cycle that is less than 10 percent.    System OperationUse this procedure to troubleshoot any suspect problems with the sensor for the left turbocharger turbine inlet temperature or the right turbocharger turbine inlet temperature.The Pulse Width Modulated Sensor (PWM) provides a signal to the ECM. The PWM signal is used to represent certain engine operating conditions. The sensors receive 8.0 0.4 VDC from a regulated power supply.The ECM performs an automatic calibration of these sensors whenever the ECM is powered and the engine has been off for at least 5 seconds.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 following components can cause problems with the power supply:
Electrical connector or wiring
Sensor
ECMThe most likely cause of a problem is a problem with an electrical connector or wiring. The least likely cause is a problem with the ECM.
Illustration 1 g03363730
Typical schematic
Illustration 2 g03318027
Terminal locations at the P1/J1 ECM connector for the turbocharger turbine inlet temperature sensors (P1-4) Digital supply (P1-5) Digital return (P1-11) Left turbo inlet temperature (P1-12) Right turbo inlet temperature
Illustration 3 g03363746
Sensor connector (Terminal A) Sensor supply (Terminal B) Sensor return (Terminal C) Signal
Illustration 4 g01234146
Table 2
Troubleshooting Test Steps    Values    Results    
1. Check for an "Active" Diagnostic Codes
A. Connect Caterpillar Electronic Technician (ET) to the service tool connector.
B. 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.
C. 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. There could also be a bad connection between a wire and a terminal.
   
Codes    
Results: No diagnostic codes are active.
Repair: There may be an intermittent problem in the harness or in a connector. If an intermittent problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct procedures for inspecting electrical connectors.
Results: One of the diagnostic codes that are listed above are active or logged.
The ECM detects a problem in one of the circuits for the exhaust temperature sensors.
Proceed to Test Step 2
   
2. Check the Digital Supply Voltage at the Sensor Connector
A. Turn the main disconnect switch to the OFF position.
B. Disconnect the suspect sensor at the sensor connector:
C. Restore the electrical power to the ECM.
D. Measure the supply voltage on the harness side of the sensor connector. Measure the voltage between terminal A and terminal B for the suspect sensor.
   
8.0 0.4 VDC    
Results: The supply voltage is 8.0 0.4 VDC. The supply voltage is reaching the sensor connector.
Proceed to Test Step 4
Results: The supply voltage is not 8.0 0.4 VDC. The supply voltage is not reaching the sensor connector.
Proceed to Test Step 3
   
3. Check the Digital Supply Voltage at the ECM
A. Turn the main disconnect switch to the OFF position.
B. Disconnect the J1/P1 ECM connectors.
C. Fabricate two jumper wires that are long enough to use as test leads at the ECM connector. Crimp connector sockets to one end of each of the jumper wires.
D. Remove the wires for the digital supply from terminal locations P1-4 and P1-5. Install a jumper wire into each of these terminal locations.
E. Connect the J1/P1 ECM connector.
F. Restore the electrical power to the ECM.
G. Measure the voltage between the jumper wires that are in terminals P1-4 and P1-5.
H. Turn the main disconnect switch to the OFF position.
I. Restore the wiring to the original configuration.
   
8.0 0.4 VDC.    
Results: The supply voltage at the ECM is 8.0 0.4 VDC.
Repair: The supply voltage at the ECM is correct. There is a problem in the wiring between the ECM and the sensor connector. Repair the connectors or wiring and/or replace the connectors or wiring.
Verify that the repair eliminated the problem.
Results: The supply voltage is not 8.0 0.4 VDC.
Repair: The voltage at the ECM is not correct. There is a problem with the ECM. Replace the ECM. Refer to Troubleshooting, "Test ECM Mode".
Note: Before you consider replacing the ECM, consult with the Dealer Solutions Network (DSN) for assistance.
Verify that the repair eliminated the problem.
   
4. Check the duty cycle for the Suspect Sensor at the Sensor Connector
A. Turn the main disconnect switch to the OFF position.
B. Remove the sensor signal wire from terminal 3 on the sensor side of the sensor connector.
C. Install a 7X-6370 Adapter Cable As (3-PIN BREAKOUT) at the sensor connector.
D. Restore the electrical power to the ECM.
E. Measure the duty cycle between the loose signal wire and terminal B (digital return) of the breakout t.
Note: Set the multimeter to "VDC". Press the "Hz" button twice so that the % symbol is displayed.
F. Turn the main disconnect switch to the OFF position.
G. Restore the wiring to the original configuration.
   
Between 10 to 90 percent.    
Results: The duty cycle is between 10 to 90 percent.
The duty cycle is correct.
Proceed to Test Step 5
Results: The duty cycle is incorrect.
Repair: Replace the sensor. Verify that no di