28860 Mariner FRAME

Illustration 1 g00668866
SchematicTest Step 1. Inspect Electrical Connectors and Wiring
Turn the keyswitch to the OFF/RESET position.
Thoroughly inspect ECM connector J1/P1, engine speed/timing sensor connector J20/P20, and engine speed/timing sensor connector J44/P44. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Check the harness and wiring for abrasion and for pinch points from the engine speed/timing sensors to the ECM.Expected Result:All connectors, pins, and sockets are completely inserted and coupled. The harness and wiring are free of corrosion, of abrasions, and of pinch points.Results:
OK - Proceed to Test Step 2.
Not OK - Repair: Repair the circuit. Verify that the repair eliminates the problem.STOPTest Step 2. Check for Diagnostic Codes
Connect the Caterpillar Electronic Technician (ET) to the data link connector.
Turn the keyswitch to the ON position.
Observe Logged Diagnostic Codes on Cat ET.Expected Result:Cat ET indicates one of the following diagnostic codes as being active or recently logged:
190-03 "Engine Speed open/short to +batt"
342-03 "Secondary Engine Speed open/short to +batt"Results:
OK - 190-03 "Engine Speed open/short to +batt" present - Repair: Disconnect the known good engine speed/timing sensor (secondary engine speed/timing sensor). Proceed to Test Step 9.
OK - 342-03 "Secondary Engine Speed open/short to +batt" present - Repair: Disconnect the known good engine speed/timing sensor (primary engine speed/timing sensor). Proceed to Test Step 9.
Not OK - Proceed to Test Step 3.Test Step 3. Check the Engine Speed/Timing Sensor
Turn the keyswitch to the OFF/RESET position.
Remove the suspect engine speed/timing sensor.
Inspect the plastic sliphead for damage.
Check the tension on the sliphead by gently prying out the sliphead 3 to 4 mm (0.12 to 0.16 inch). Push in the sliphead from the extended position.
Extend the sliphead.Expected Result:Pushing in the sliphead from the extended position should take at least 22 N (5 lb) of force.Results:
OK - The engine speed/timing sensor and the sliphead are undamaged. The tension on the sliphead is normal. Reinstall the sensor.Repair: Reinstall the engine speed/timing sensor. Refer to Disassembly and Assembly, "Speed/Timing Sensor - Remove and Install". Proceed to Test Step 4.
Not OK - The engine speed/timing sensor or the sliphead is damaged, or the sliphead has insufficient tension.Repair: Replace the engine speed/timing sensor. Refer to Disassembly and Assembly, "Speed/Timing Sensor - Remove and Install".Calibrate the new sensor. Refer to Troubleshooting, "Engine Speed/Timing Sensor - Calibrate".Verify that the repair eliminates the problem.STOPTest Step 4. Check the Engine Speed on Cat ET
Turn the keyswitch to the ON position and crank the engine.
Observe the engine speed on Cat ET while you crank the engine.Expected Result:Cat ET displays a steady engine speed between 100 and 250 rpm while the engine is cranking and the engine starts.Results:
OK - The engine speed/timing sensor is operating normally at this time.Repair: Reconnect the known good engine speed/timing sensor.If you are troubleshooting an intermittent problem, refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
No Engine Speed - The engine does not start and the engine speed does not appear on Cat ET. Proceed to Test Step 5.
Engine Speed OK/Engine Will Not Start - The engine will not start. Engine speed appears on Cat ET.Repair: Reconnect the known good engine speed/timing sensor.Proceed to Troubleshooting, "Engine Cranks But Will Not Start".STOPTest Step 5. Check the Supply Voltage at the Sensor Connector
Install a 7X-6370 Adapter Cable As (3-PIN BREAKOUT) at the suspect connector for the engine speed/timing sensor.
Turn the keyswitch to the ON position.
Measure the voltage between Terminal A (+V Timing) and Terminal B (Digital Return) of the breakout.
Turn the keyswitch to the OFF/RESET position.Expected Result:The supply voltage is 12.5 1.0 VDC.Results:
OK - The engine speed/timing sensor is receiving correct supply voltage. Proceed to Test Step 6.
Not OK - Proceed to Test Step 7.Test Step 6. Check the Isolated Signal Voltage at the Sensor
Remove the wire from Terminal C (Signal) at the harness side of the suspect connector for the engine speed/timing sensor.
Measure the voltage between Terminal B (Digital Return) and Terminal C (Signal) of the breakout. Perform this step with the keyswitch in the ON position before you crank the engine and while you crank the engine.
Turn the keyswitch to the OFF/RESET position.
Reinstall the wire in Terminal C (Signal) of the suspect connector for the engine speed/timing sensor. Expected Result:The voltage is less than 3.0 VDC or the voltage is greater than 10.0 VDC with the keyswitch in the ON position. The voltage varies between 2.0 VDC and 4.0 VDC during engine cranking.Results:
OK - The engine speed/timing sensor is producing an output signal. Proceed to Test Step 8.
Not OK - The engine speed/timing sensor is not producing a valid output signal.Repair: Replace the engine speed/timing sensor. Refer to Disassembly and Assembly, "Speed/Timing Sensor - Remove and Install".Calibrate the new sensor. Refer to Troubleshooting, "Engine Speed/Timing Sensor - Calibrate".Verify that the repair eliminates the problem.STOPTest Step 7. Check the Supply Voltage at the ECM
Turn the keyswitch to the OFF/RESET position.
Install a 7X-1715 Adapter Cable (40-PIN BREAKOUT) at ECM connector J1/P1.
Turn the keyswitch to the ON position.
Illustration 2 g00668980
J1/P1 breakout
Measure the voltage between P1:29 (Digital Return) and P1:32 (+V Timing) at the breakout.
Turn the keyswitch to the OFF/RESET position.Expected Result:The voltage is 12.5 1.0 VDC.Results:
OK - There is an open circuit or excessive resistance in the harness between the ECM and the sensor.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOP
Not OK - Repair: Ensure that the ECM is receiving the correct supply voltage. Refer to Troubleshooting, "Electrical Power Supply Circuit - Test". If the ECM is receiving the correct supply voltage, proceed to Test Step 8.Test Step 8. Check for a Short Circuit in the Wiring Harness
Turn the keyswitch to the OFF/RESET position.
Disconnect ECM connector J1/P1 and the suspect connector for the engine speed/timing sensor.
Measure the following resistances at the suspect engine speed/timing sensor (harness side).
Terminal A (+V Timing) and Terminal B (Digital Return)
Terminal A (+V Timing) and Terminal C (Signal)
Terminal B (Digital Return) and Terminal C (Signal)
Terminal A (+V Timing) and engine ground
Terminal B (Digital Return) and engine ground
Terminal C (Signal) and engine groundExpected Result:The resistance is greater than 20,000 Ohms for each measurement.Results: