PIN AS 4979321 - Caterpillar

Probable Causes
There is a problem with the input for the keyswitch.
Ignition system
Fuel supply
Loss of power
E-stop signal
Detonation systemRecommended Repairs
Table 1
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Look for active codes that are associated with the system for the event code.
Codes
Result: An associated code is active.
Repair: Troubleshoot any associated codes before continuing with this test.
Result: An associated code is NOT present.
Proceed to Test Step 2.
2. Verify that the Voltage on the Keyswitch Circuit is Stable
An engine shutdown or an engine overspeed may occur due to a problem with the input for the keyswitch for one of the following:
- Actuator for the throttle
- Actuator for the turbocharger compressor bypass valve
- Actuator for the fuel metering valve
- ECM
A. Verify that the input for the keyswitch to the actuators is not intermittent.
Keyswitch Input
Result: The input for the keyswitch to the actuators is NOT intermittent.
Proceed to Test Step 3.
Result: The input for the keyswitch to the actuators is intermittent.
Repair: Remedy the cause for the intermittent keyswitch input.
3. Check the Ignition System
A. Ensure that current parts are used for the following components:
- Transformers
- Extenders
- Spark plugs
Inspect the ignition system for the following conditions:
1. Check the connection between the ignition transformer and the extender. A loose connection can cause arcing and misfires.
2. Check the connection between the extender and the spark plug for a loose connection or for pin holes that are caused by arcing. Both conditions can cause misfires.
3. Check the extender for corrosion on the spring. Corrosion may cause arcing through the extender.
4. Check for corrosion on the terminal of the spark plug and check for wear on the electrode. Both conditions can cause misfires.
Excessive moisture can cause misfire.
Maintain the spark plug according to the engine Operation and Maintenance Manual.
Ignition System
Result: The Ignition System is OK.
Proceed to Test Step 4.
Result: A faulty component was identified.
Repair: Repair or replace the faulty component.
4. Check the Fuel Supply
A. Make sure that fuel is supplied at a sufficient pressure that is stable. Make sure that the size of the fuel line is sufficient. Inspect the fuel system for leaks.
The following conditions can cause the engine to malfunction:
- Low fuel pressure
- High fuel pressure
- Poor fuel quality
B. Make sure that the fuel pressure is correct. When possible, interview the operator to determine if fuel quality is in question. Try to determine if the source of the fuel was changed.
Inspect the fuel system components:
- Fuel filter
- Gas pressure regulator
- Gas shutoff valve
- Fuel metering valve
Fuel
Result: A faulty component was identified.
Repair: Repair or replace the faulty component.