GEAR AS-RING 9U9846 - Caterpillar

Probable Causes
Diagnostic codes
Accessory equipment
Fuel system inspection
Low compression (cylinder pressure)
Electronic unit injectorsRecommended Actions
Note: The procedures have been listed in order of probability. Complete the procedures in order.
Table 1
Troubleshooting Test Steps Values Results
1. Diagnostic Codes
A. Establish communication between the electronic service tool and the Electronic Control Module (ECM) . Refer to Troubleshooting, "Electronic Service Tools", if necessary.
B. Check if any codes are active or logged.
Diagnostic code
Result: A code is active or logged.
Repair: Troubleshoot any codes before continuing with this procedure.
Result: A code is not active or logged.
Proceed to Test Step 2.
2. Accessory Equipment
A. Check all accessory equipment for faults that may create excessive load on the engine.
Accessories
Result: An engine accessory is creating an excessive load.
Repair: Repair or replace the engine accessory.
Result: An engine accessory is not creating an excessive load.
Proceed to Test Step 3.
3. Fuel System Inspection
A. Check that the fuel shut-off valve is in the OPEN position.
B. If the temperature is below 0 °C (32 °F), check for solidified fuel (wax).
C. Check for fuel supply lines that are restricted.
D. Check that the low-pressure fuel lines are correctly installed.
E. Check the pressures in the fuel system. Refer to Systems Operation, Testing, and Adjusting, "Fuel System Pressure - Test"
F. Check the diesel fuel for contamination. Refer to Systems Operation, Testing, and Adjusting, "Fuel Quality - Test".
G. Check for air in the fuel system. Refer to Systems Operation, Testing, and Adjusting, "Air in Fuel - Test".
H. Ensure that the fuel system has been primed. Refer to Systems Operation, Testing, and Adjusting, "Fuel System - Prime".
Fuel System
Result: A defect was found in the fuel system.
Repair: Make any necessary repairs.
Result: No defects found.
Proceed to Test Step 4.
4. Low Compression (Cylinder Pressure)
A. Perform a compression test. Refer to Systems Operation, Testing, and Adjusting, "Compression - Test ".
Low compression
Result: Low compression is recorded on one or more cylinders.
Repair: Possible causes of low compression are shown in the following list:
Loose glow plugs
Faulty piston
Faulty piston rings
Worn cylinder bores
Worn valves
Faulty cylinder head gasket
Damaged cylinder head
Make any repairs, as necessary.
Result: No faults found.
Proceed to Test Step 5.
5. Electronic Unit Injectors
A. Use the electronic service tool to check for active diagnostic codes that relate to the fuel injectors.
Diagnostic codes
Result: There are active diagnostic codes for the fuel injectors
Repair: Troubleshoot the active diagnostic codes. Refer to Troubleshooting, "Diagnostic Trouble Codes"
Result: All injectors are OK.
Contact the Dealer Solution Network (DSN).