44484 Mercury PINION GEAR

Introduction
On the pages that follow is a list of possible problems. Several common problems are covered but these problems are not arranged in any particular sequence.Before checking the list of problems, check the SCM display for any diagnostic codes that may be shown. These codes will aid in finding the problem (see Diagnostic Code Interpretation).Identify your particular type of problem from the Problem List, then go directly to that problem. However, when you begin the procedure for that problem, start at Step 1 and follow through the step by step procedure. The steps in a particular problem provide a definite sequence to be followed for a logical, one by one elimination of many variables. These steps are arranged in order from the more probable/easiest to check, to the less probable/more complex to check.When the cause of the problem is found and corrected, stop the test. Do not continue through the complete procedure just because it is there.Test Instruments
Caterpillar Digital Multimeter (6V7070) - can be used for many of the voltage and resistance checks. Rectifiers can also be checked with the special diode function. For further information on using the digital multimeter, see Special Instruction, Form SEHS7734.Diagnostic Code Interpretation
Diagnostic codes are displayed on the same display as the service hours, engine speed, battery voltage, engine oil pressure, and engine coolant temperature. When a diagnostic code is displayed, the arrow that indicates which of the above parameters are displayed will be missing and a flashing "dIAG" will be displayed. If several faults are present, the diagnostic codes will be displayed in sequence. The diagnostic code can be cleared from display by turning the Engine Control Switch (ECS) to the reset position. Before attempting a repair, move the ECS to the reset position and restart engine to see if problem recurs. See the Problem List for display codes.Troubleshooting Problem List
1. SCM Display = 01 dIAG, no magnetic speed pickup (speed sensor) signal.2. SCM Display = 02 dIAG, no oil pressure/temperature sensor (transducer) signal.3. SCM Display = 03 dIAG, a problem with inputs from the ECS.4. SCM Display = 04 dIAG, loss of setpoints programmed into the SCM memory.5. SCM Display = 05 dIAG, engine shutdown with no shutdown command from the SCM.6. SCM Display = 06 dIAG, internal failure of SCM or unstable voltage supply.7. SCM Display = 07 dIAG, internal SCM programming switch does not match program.8. SCM Display = 08 dIAG, temperature probe problem. 9. Engine cranks but does not start or shuts down immediately after starting.10. Engine does not crank (if equipped with an electric starter).11. Starter remains engaged or continues to run after engine has started (If equipped with an electric starter).12. Engine shutdown occurs, all six LED fault indicators on the SCM flash.13. LED fault indicator on the SCM will not reset.14. Engine shutdown occurs, overcrank LED is lit.15. Engine shutdown occurs, overspeed LED is lit.16. Engine shutdown occurs, low oil pressure LED is lit.17. Engine shutdown occurs, high coolant temperature LED is lit.18. Engine shutdown occurs, emergency stop LED is lit.19. Engine shutdown occurs, auxillary LED is lit.20. No engine shutdown when a fault occurs. 21. Engine shutdown with no LED's lit or diagnostic codes on SCM.22. Remote annunciator or control panel alarm module, data link controlled LED's all flash at a rate of once per two seconds (.5 Hz). Problem 1: SCM Display = 01 dIAG, no magnetic speed pickup (speed sensor) signal. Step 1. Test Procedure:Disconnect speed sensor leads (not ground wires) from terminals 1 and 7 on the SCM and measure resistance with a multimeter. Also measure resistance between speed sensor leads and ground. Probable Cause:1. Resistance between speed sensor leads is between 400 and 520 ohms. Lead to grond resistance is above 5000 ohms. Speed sensor wiring is okay. Go to Step 2.2. Resistance is below 400 ohms. Short circuit in wiring or sensor. Repair wiring or replace speed sensor as needed.3. Resistance is above 520 ohms. Wire is broken or connector is defective. Repair broken wire or bad connection or replace speed sensor as needed.4. Resistance between sensor leads and ground is below 5000 ohms. Speed sensor is grounded. Repair wiring harness or replace speed sensor as needed. Step 2. Test Procedure:Reconnect speed sensor leads to terminals 1 and 7 on the SCM. Use a 6V7070 Multimeter (or a meter of known accuracy) to measure AC voltage across terminals 1 and 7 on the SCM while cranking the engine. Be sure that you can reach 250 rpm. Probable Cause:1. Speed sensor voltage is 1.0 volt AC or greater. Attempt to start. If 01 dIAG reappears, replace speed sensor. If 01 dIAG still appears, replace SCM.2. Speed sensor voltage is below 1.0 volt AC. Adjust speed sensor gap (see Service Procedure D). If speed sensor voltage is still low, replace speed sensor. Problem 2: SCM Display = 01 dIAG, no oil pressure/temperature sensor (transducer) signal. Step 1. Test Procedure:Measure the voltage between terminal 4 and battery negative of the SCM. Disconnect the 3 pin connector at the pressure/temperature sensor (transducer) and measure the voltage between terminal 4 and battery negative. Disconnect the wire from terminal 4 and measure the voltage between terminal 4 of the SCM and battery negative. Probable Cause:1. Voltage is between 11 and 15 VDC in all cases. Power supply is okay. Go to Step 2.2. Voltage is above 20 VDC in all cases. Replace SCM. It is likely that pressure/temperature transducer has also been damaged.3. Voltage is above 15 VDC but below 20 VDC in all cases or below 11 VDC in all cases. Replace SCM.4. Voltage goes from below 11 VDC to between 11 and 15 VDC when the 3 pin connector is disconnected. Replace pressure/temperature transducer.5. Voltage goes from below 11 VDC to between 11 and 15 VDC when wire to terminal 4 is disconnected. Repair grounded