Troubleshooting

Table 32
Troubleshooting Test Steps
Values Results
1. Diagnostic Codes
A. Establish communication between the electronic service
tool and the Electronic Control Module (ECM). Refer to Trou-
bleshooting, “Electronic Service Tools”, if necessary.
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. Engine Accessories and Transmission
A. Check that the engine accessories and transmission are
operating correctly.
B. Remove and inspect any engine accessories that may be
adding unexpected load to the engine.
Engine accesso-
ries and
transmission
Result: The engine accessories and transmission are not OK.
Repair: Make the necessary repairs.
Result: The engine accessories and transmission are OK.
Proceed to Test Step 3.
3. ECM Parameters
A. Use the electronic service tool to verify that the correct en-
gine parameters are being used. Refer to Troubleshooting,
“Configuration Parameters” for additional information.
Parameters Result: The parameters are not configured correctly.
Repair: Correctly configure the parameters.
Verify that the configuration change eliminated the fault.
Result: The parameters are configured correctly.
Proceed to Test Step 4.
4. Throttle Signal From the Throttle Position Sensor (if
equipped)
A. If a fault is suspected in the throttle sensor, refer to Trou-
bleshooting, “Speed Control - Test”.
Throttle position
sensor faults
Result: The throttle position sensor or the associated wiring is
faulty.
Repair: Repair or replace the throttle position sensor or the
associated wiring.
Result: The throttle position sensor and the associated wiring
are OK.
Proceed to Test Step 5.
5. Air Intake and Exhaust System
A. Check the air filter restriction indicator, if equipped. Clean
plugged air filters or replace plugged air filters. Refer to the
Operation and Maintenance Manual.
B. Check the air inlet and exhaust system for restrictions and/
or leaks. Refer to Systems Operation, Testing and Adjusting,
“Air Inlet and Exhaust System - Inspect”.
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 6.
(continued)
78 UENR0612-07
Symptom Troubleshooting
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