GMC Yukon 2000–2006
Common on this vehicle:LeakMisfire or rough idleNoiseWarning light
Record by record
6 records state a cause or a remedy. Each record is shown as short labels in the order fault → finding the cause → correction. Press a label to narrow to the records that state it.
Component named as the cause
A ribbon is as wide as the records that state both of its ends (only the commonest are drawn). A record that names several symptoms or components runs through each. Orange is records that say the fault came back or was not fixed. Results come from owners’ reports only; one that does not say is “result not stated”. None of this is a likelihood of a cause or a rate at which work succeeds.
Read the records one by one (2)
Known issuesSingle-cylinder misfire (P0300-P0308) and/or chirp, squeak or tick at camshaft speed: worn cam lobe / lifter, valve or valve spring2
Manufacturer communication2002–2006 GMC YUKON DENALI ・ 2018-11-13(4 earlier editions of this document folded here)
Service Engine Soon Lamp, Misfire, Engine Noise Diagnostic Information
1Fault
- Customers may complain of an SES light, engine misfire, and/or engine noise.
- If the SES light is on, there will be a P0300-P0308 DTC with misfires counting on a single cylinder, which may or may not be felt.
- A verified noise is not eliminated by canceling fuel injectors and occurs at camshaft speed (half of crankshaft speed).
2Finding the cause
- Valve Spring: broken
- Active Fuel Management Lifter: failed
- Valve: defective
- Camshaft Lobe: worn
- Lifter Roller: worn
Possible causes
- If SI diagnosis does not isolate the cause, it may be a worn camshaft lobe and/or lifter roller, a sticking valve, valve leakage, a broken valve spring, or a collapsed AFM (Active Fuel Management) lifter.
Steps to confirm (in the document’s order)
- During the noise, press with a wooden hammer handle on the rocker arms at the valve side, push rod side, and side of the rocker to find which one is making noise.
- If pressure on the valve side of the rocker changes the noise, it is most likely a lifter and/or cam lobe concern on that cylinder.
- Measure the cam lobe lift at the push rod side of the rocker arm.
- A good indicator of a sticking valve is engine misfires that continue to count on an aggressive deceleration with engine braking.
- Release the air pressure from the cylinder and work the valve up and down in the guide while turning it 360 degrees; if any binding is felt, a stem to guide clearance concern exists.
3Correction
Repair
- If a worn camshaft lobe or lifter roller is found, follow SI procedures to replace the camshaft and all lifters.
- Also replace the plastic lifter guide for the lifter that had the damaged cam lobe and/or lifter roller.
- Refer to the latest version of PIP4753 for decarboning instructions.
- If a broken valve spring is found, replace the broken valve spring as necessary.
Caution
- If an AFM lifter concern is suspected, refer to the latest version of PIP4568 for additional information.
Read the sentences of the record
From the manufacturer’s document
- Applies to:Applies to GMC Yukon models, 2002 - 2018, with a V8 engine.
- Condition:Customers may complain of an SES light, engine misfire, and/or engine noise.
- Condition:If the SES light is on, there will be a P0300-P0308 DTC with misfires counting on a single cylinder, which may or may not be felt.
- Condition:A verified noise is not eliminated by canceling fuel injectors and occurs at camshaft speed (half of crankshaft speed).
- Cause:If SI diagnosis does not isolate the cause, it may be a worn camshaft lobe and/or lifter roller, a sticking valve, valve leakage, a broken valve spring, or a collapsed AFM (Active Fuel Management) lifter.
- Confirm:During the noise, press with a wooden hammer handle on the rocker arms at the valve side, push rod side, and side of the rocker to find which one is making noise.
- Confirm:If pressure on the valve side of the rocker changes the noise, it is most likely a lifter and/or cam lobe concern on that cylinder.
- Confirm:Measure the cam lobe lift at the push rod side of the rocker arm.
- Repair:If a worn camshaft lobe or lifter roller is found, follow SI procedures to replace the camshaft and all lifters.
- Repair:Also replace the plastic lifter guide for the lifter that had the damaged cam lobe and/or lifter roller.
- Confirm:A good indicator of a sticking valve is engine misfires that continue to count on an aggressive deceleration with engine braking.
- Confirm:Release the air pressure from the cylinder and work the valve up and down in the guide while turning it 360 degrees; if any binding is felt, a stem to guide clearance concern exists.
- Repair:Refer to the latest version of PIP4753 for decarboning instructions.
- Confirm:Typically, the Cylinder Leakage Test outlined in SI should isolate valve leakage.
- Repair:If a broken valve spring is found, replace the broken valve spring as necessary.
- Caution:If an AFM lifter concern is suspected, refer to the latest version of PIP4568 for additional information.
Open the manufacturer’s document (PDF) ↗ The points above were read from this document.
- Remedy
- This Preliminary Information communication provides information to the technician about vehicles that have a Service Engine Soon Malfunction Indicator Lamp on, engine misfire, and/or engine noise. Technician may find Diagnostic Trouble Codes P0300-P0308. If published Service Information diagnostics does not isolate the cause of this concern technician should check for a worn camshaft lobe and/or lifter roller, a sticking valve, valve leakage, a broken valve spring, and a collapsed active fuel management lifter.
Manufacturer communication2000–2006 GMC YUKON DENALI ・ 2017-08-15
Service Engine Soon Lamp and Engine Misfire Information
1Fault
2Finding the cause
3Correction
What the documents say to do
Single-cylinder misfire (P0300-P0308) and/or chirp, squeak or tick at camshaft speed: worn cam lobe / lifter, valve or valve springConfirm
- If pressing on the valve side of the rocker changes the noise, a lifter and/or cam lobe concern on that cylinder is most likely.
Repair
- If a worn camshaft lobe or lifter roller is found, follow SI procedures to replace the camshaft and all lifters.
- Also replace the plastic lifter guide for the lifter that had the damaged cam lobe and/or lifter roller.
Caution
- A damaged cam lobe is easy to overlook when inspecting through the lifter bores; unworn lifter rollers do not mean the cam lobes are okay.
Read the sentences of the record
Open the manufacturer’s document (PDF) ↗ What is shown here is NHTSA’s summary; the procedure is in the document itself.
- Remedy
- This Preliminary Information communication provides information to the technician about vehicles that have a Service Engine Soon Malfunction Indicator Lamp on, engine misfire, and/or engine noise. Technician may find Diagnostic Trouble Codes P0300-P0308. If published Service Information diagnostics does not isolate the cause of this concern technician should check for a worn camshaft lobe and/or lifter roller, a sticking valve, valve leakage, a broken valve spring, and a collapsed active fuel management lifter.
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