CONE 2N3254 - Caterpillar

Note: If this fault occurs only under load, refer to Troubleshooting, "Acceleration Is Poor or Throttle Response Is Poor".Probable Causes
Diagnostic codes
Fuel pump calibration
Accessory and/or parasitic loads
Throttle signal for the throttle position sensor (if equipped)
Throttle signal for the CAN data link (if equipped)
Air intake and exhaust system
Fuel supply
Low compression (cylinder pressure)
Electronic unit injectors
Individual malfunctioning cylindersRecommended 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. Download the Product Status Report before troubleshooting or clearing any diagnostic codes.
Note: The downloaded information will be required by the DSN if troubleshooting assistance is needed.
C. Use the electronic service tool to check for active or logged codes.
Diagnostic codes
Result: There are active or logged codes.
Repair: Troubleshoot any codes before continuing with this procedure.
Result: There are no active or logged codes.
Proceed to Test Step 2.
2. Fuel Pump Calibration
A. Establish communication between the electronic service tool and the Electronic Control Module (ECM). Refer to Troubleshooting, "Electronic Service Tools", if necessary.
B. Perform the "Fuel Pump Learn" procedure.
Fuel pump calibration
Result: The symptom is eliminated.
Repair: Return the unit to service.
Result: The symptom is still present.
Proceed to Test Step 3.
3. Accessory and/or Parasitic Loads
A. Check all accessory equipment for problems that may create excessive load on the engine.
B. Check for any excess parasitic load on the engine.
Parasitic loads
Result: There is an excessive load on the engine.
Repair: Diagnose and repair the fault.
Verify that the repair eliminated the fault.
Result: There is not an excessive load on the engine.
Proceed to Test Step 4.
4. Throttle Signal for the Throttle Position Sensor (If Equipped)
A. Use the electronic service tool and observe the signal for the throttle position sensor. Make sure that the throttle reaches the 100% raw position and the calibrated position.
Analog throttle input
Result: The throttle signal is erratic or does not reach the 100% raw position or the calibrated position.
Repair: Refer to Troubleshooting, "Speed Control (Analog) - Test".
Result: The throttle signal is OK.
Proceed to Test Step 5.
5. Throttle Signal for the CAN Data Link (If Equipped)
A. Use the electronic service tool and observe the signal for the throttle position sensor. Make sure that the throttle reaches the 100% raw position and the calibrated position.
CAN data link
Result: The throttle signal is erratic or does not reach the 100% raw position or the calibrated position.
Repair: Refer to Troubleshooting, "CAN Data Link - Test".
Result: The throttle signal is OK.
Proceed to Test Step 6.
6. Air Intake and Exhaust System
A. Check the air filter restriction indicator, if equipped.
B. Check the air inlet and exhaust system for restrictions and/or leaks.
Restrictions
Result: The air filter is plugged.
Repair: Clean or replace the air filter. Refer to the Operation and Maintenance Manual for further information.
Result: There are restrictions in the air inlet or exhaust system.
Repair: Make the necessary repairs, Verify that the repair eliminated the fault.
Result: There are no restrictions in the air inlet or exhaust system.
Proceed to Test Step 7.
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