0308947 JOHNSON LEAF VALVE

Probable Causes
Diagnostic codes and event codes
Slow cranking speed
Battery condition
Keyswitch power to the Electronic Control Module (ECM) and the Fuel Control Valve
ECM supply voltage
Engine speed/timing signal
Low-pressure fuel system
High-pressure fuel system
Injector bypass fuel flow
Fuel quality
Starting aids
Gear train problemRecommended Actions
Diagnostic Codes and Event Codes
Connect Caterpillar Electronic Technician (ET) to the service tool connector. Check for active diagnostic codes and event codes.Look for active diagnostic codes or active event codes related to the following engine systems:
Low-pressure fuel system
High-pressure fuel system
Engine speed/timing sensors
Engine shutdown devicesCheck for event codes that are logged repeatedly. Several logged diagnostic codes may be evidence of an impending problem. Check for logged events that have a severity of level 3. If a problem has been discovered, perform the necessary repairs. If necessary, use the appropriate circuit test to troubleshoot any active diagnostic codes.Use Cat ET to confirm the status of any shutdown devices that are installed on the application. If the application has any shutoff devices that are latched mechanically, ensure that the devices have been reset. Also, check the status of any aftermarket shutdown devices that may be installed on the application. If engine starting is being prevented by one of these devices, refer to the OEM information for details.Slow Cranking Speed
Use Cat ET to check the engine speed while you crank the engine. If the engine cranks too slowly, the engine will not start. Typically, for an engine to start, the engine speed must be greater than 100 rpm for four revolutions of the crankshaft.If the engine has a low cranking speed, check for the following problems:
Low voltage for an electric starting system
Low air pressure for an air start system
Excess parasitic load
Engagement of a single starting motor on a dual starting motor systemBattery Condition
Check the charge on the batteries for the engine. Charge the batteries, if necessary. Refer to Special Instruction, SEHS7633, "Battery Test Procedure".Load-test the batteries. Refer to Special Instruction, SEHS9249, "Use of 4C-4911 Battery Load Tester for 6, 8 and 12 Volt Lead Acid Batteries".Keyswitch Power to the Electronic Control Module and the Fuel Control Valve
Obtain a 7X-1708 Multimeter Probe (RED) and a 7X-1709 Multimeter Probe (BLACK). Use the probes to check the voltage between terminal P1-69 (−Battery) and terminal (70) (keyswitch) at the ECM connector.
Crank the engine. Use a multimeter to measure the keyswitch power at the ECM while the engine is cranked.
Remove the multimeter probes from the engine.
Use the multimeter probes to check the voltage between terminal 8 (keyswitch) and terminal 1 (return) of the connector for the fuel control valve.
Crank the engine. Use a multimeter to measure the keyswitch power at the fuel control valve while the engine is cranked.
Remove the multimeter probes from the engine. The keyswitch power must be greater than 18 VDC in order for the engine to start. If the keyswitch power is below 18 VDC, troubleshoot the problem. Refer to Troubleshooting, "Electrical Power Supply - Test" for details that are related to troubleshooting a low voltage at the keyswitch circuit.ECM Supply Voltage
Install a 7X-1708 Multimeter Probe (RED) and a 7X-1709 Multimeter Probe (BLACK) onto the test leads of a multimeter.
Check the battery supply voltage at the ECM during engine cranking.
Check the voltage between terminal locations P1-48 (+Battery) and P1-61 (−Battery) while you crank the engine.
Check the voltage between terminal locations P1-52 (+Battery) and P1-61 (−Battery) while you crank the engine.
Check the voltage between terminal locations P1-53 (+Battery) and P1-61 (−Battery) while you crank the engine.
Check the voltage between terminal locations P1-55 (+Battery) and P1-61 (−Battery) while you crank the engine.
Check the voltage between terminal locations P1-57 (+Battery) and P1-61 (−Battery) while you crank the engine.
Remove the multimeter probes from the engine. The supply voltage must be greater than 18 VDC at the ECM in order for the engine to start. If the supply voltage is below 18 VDC, troubleshoot the problem. Refer to Troubleshooting, "Electrical Power Supply - Test" for details that are related to troubleshooting a low voltage at the keyswitch circuit.Engine Speed/Timing Signal
Use Cat ET to monitor the following status parameters while you crank the engine:
"Engine Speed Primary Sensor"
"Engine Speed Secondary Sensor"
"Engine RPM from Tertiary Speed Sensor"
"Primary Engine Speed Sensor Timing Pattern Status"
"Secondary Engine Speed Sensor Timing Pattern Status"
"Engine Tertiary Speed Sensor Timing Pattern Status"Ensure that all three of the engine speed sensors are indicating an engine rpm during cranking. Also, ensure that the status of signal patterns for each of the engine speed/timing sensors is "Detected".Note: The engine will not start if the signal from more than one sensor is missing.If the operation of any of the engine speed/timing sensors is suspect, refer to Troubleshooting, "Speed/Timing - Test" for information that is related to troubleshooting the engine speed/timing circuit.Low Pressure Fuel System
Perform a visual inspection of the fuel system components.
Use Cat ET to verify that the status indicator for "Cold Mode" is active for cold weather starting.
Check the fuel pressure during engine cranking. Check the filtered fuel pressure. Refer to Systems Operation/Testing and Adjusting for the correct pressure values.
If the fuel pressure is OK, check for air in the fuel system. Refer to Systems Operation/Testing and Adjusting for details.
If the fuel pressure is low, replace the fuel filters. If the problem is not found, refer to Troubleshooting, "Fuel Pressure is Low" for detailed troubleshooting that is related to the low-pressure fuel system. High Pressure Fuel System
Use Cat ET to monitor the "Fuel Rail Pressure (absolute)" status parameter while you crank the engine.Ensure that the status of the "Fuel Rail Pressure (absolute)" parameter is greater than approximately 40,000 kPa (5800 psi) while you crank the engine. If the fuel rail pressure is below this specification, refer to Troubleshooting, "Fuel Rail Pressure Is Low" in order to troubleshoot the symptom.Injector Bypass Fuel Flow
Excessive injector bypass fuel flow is returned to the tank through the fuel manifold. Perform the following procedure to check for excessive injector bypass flow at the injector:
Contact with high pressure fuel may cause fluid penetration and burn hazards. High pressure fuel spray may cause a fire hazard. Failure