
(Table 13, contd)
Troubleshooting Test Steps
Values
Results
3. Valve Train Components
A. Check the valve lash. Refer to Troubleshooting, “Valve Lash Is
Excessive”.
B. Check for damage to valve train components. Remove the valve
cover from the suspect cylinders. Check the following items for
damage:
· Valve springs
· Rocker shaft
· Pushrods
· Camshaft followers
Refer to the Disassembly and Assembly for additional information.
Valve train
Result:
Valve train components are damaged.
Make the necessary repairs, Verify that the repair has elimi-
nated the noise.
Result:
The valve train components are not damaged.
Proceed to Test Step 4.
4. Electronic Unit Injectors
A. Use the electronic service tool to check for active diagnostic co-
des that relate to the electronic unit injectors. Troubleshoot any ac-
tive diagnostic codes before continuing with this procedure.
Diagnostic
codes
Result:
There is an active diagnostic code for the injectors.
Troubleshoot any active injector diagnostic codes. Refer to
Troubleshooting, “Diagnostic Trouble Codes”.
Result:
There are no active diagnostic codes for the
injectors.
Proceed to Test Step 5.
5. Pistons
A. Inspect the pistons for damage and wear.
Pistons
Result:
One or more pistons are worn or damaged.
Replace any worn or damaged parts.
Verify that the repair has eliminated the noise.
Result:
All pistons are OK.
Contact the Dealer Solution Network (DSN).
i05992069
Diesel Particulate Filter Active
Regeneration Occurrence Is
Excessive
Note:
This procedure is only applicable to engines
equipped with a wall flow Diesel Particulate Filter
(DPF) and a DPF differential pressure sensor.
An active regeneration of the DPF will normally be
initiated by the soot model that is calculated in the
Electronic Control Module (ECM). If the differential
pressure across the DPF is too high, the ECM will
initiate an active regeneration based on the DPF
differential pressure.
Probable Causes
• Insulation on the exhaust duct (if equipped)
• Diagnostic codes
• Maintenance schedule
• Low compression (cylinder pressure)
• Electronic unit injectors
• Individual malfunctioning cylinders
Recommended Actions
Note:
The procedures have been listed in order of
probability. Complete the procedures in order.
46
UENR0612
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