P0302 on 2010-2017 Chevrolet Suburban: Cylinder 2 Misfire Causes and Fixes

What's Unique About the 2010-2017 Chevrolet SUBURBAN

The 2010-2017 Suburban V8 engines are known for issues with their Active Fuel Management (AFM) system, also called Dynamic Fuel Management (DFM). This system deactivates cylinders (1, 4, 6, and 7) to save fuel, but the specialized lifters can fail, get stuck, and cause a persistent misfire. While a P0302 code points to a non-AFM cylinder, oiling issues, aeration, and contamination caused by the AFM system can still lead to the failure of standard lifters or other components. A failed AFM lifter is a well-documented and serious potential cause for misfire codes on this specific platform.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Generation note: This range covers two Suburban generations. The 10th generation (2010-2014) primarily used the 5.3L LC9 V8. The 11th generation (2015-2017) introduced the EcoTec3 engine family, including the 5.3L L83 and 6.2L L86 with direct injection. While both generations have AFM systems prone to lifter failure, the fuel and ignition components (like injectors and coils) are different. TSBs like 15-06-01-002L specifically cover the 2015-2017 models for AFM-related misfires.

Symptoms You May Notice

• Rough or shaky idle
• Hesitation or stumbling during acceleration
• Noticeable loss of engine power
• Solid or flashing Check Engine Light
• Engine shaking or vibrating
• A ticking or tapping noise from the engine, which can indicate a lifter problem
• Reduced fuel economy

Most Likely Causes

1. Worn or Fouled Spark Plug 🔴 High Probability
   How to confirm: Remove the spark plug from cylinder 2 and inspect it for wear, carbon buildup, oil fouling, or a cracked insulator. A user on Tahoe Yukon Forum noted their misfire was resolved after finding a spark plug had broken at the top. Compare it to a plug from a different cylinder.
   Typical fix: Replace the spark plug. It is recommended to replace all 8 spark plugs at the same time for even performance. Use high-quality OEM or aftermarket plugs.
   Est. part cost: $5-$20 per plug
2. Failed Ignition Coil 🔴 High Probability
   How to confirm: Swap the ignition coil from cylinder 2 with another cylinder (e.g., cylinder 4, the next one back on the passenger side). Clear the codes and drive the vehicle. If the code changes to P0304, the coil is faulty.
   Typical fix: Replace the faulty ignition coil. ACDelco is the OEM supplier. 🎬 Watch: How to replace ignition coils on your Suburban.
   Est. part cost: $40-$90
3. Bad Spark Plug Wire 🟡 Medium Probability A GM Technical Service Bulletin (TSB #PIP4819A) specifically mentions inspecting and replacing loose spark plug wires as a cause for misfires on 2010 models. Wires should be fully seated with an audible click.
   How to confirm: Visually inspect the wire for cylinder 2 for any signs of damage, corrosion, or a loose connection at the coil or spark plug. You can also test its resistance with a multimeter.
   Typical fix: Replace the spark plug wire. It's often best to replace the full set.
   Est. part cost: $50-$120 for a set
4. Failed Active Fuel Management (AFM) Lifter or Related Component 🟡 Medium Probability The AFM lifters in GM's 5.3L and 6.2L engines are a known failure point. They can become mechanically stuck or collapsed, preventing the valve from opening and causing a misfire. Multiple TSBs exist regarding this issue, such as 15-06-01-002L. Oil aeration or contamination can cause the internal locking pins to fail.
   How to confirm: This is more difficult to diagnose. It often starts with a ticking noise. 🎬 See this video for diagnosing AFM lifter noise. A mechanic can perform a cylinder deactivation test with a scan tool. A compression test may show low or zero compression on cylinder 2. Final confirmation requires removing the valve cover to observe valve movement. A collapsed lifter may be visibly compressible by hand, unlike a good one.
   Typical fix: This is a major repair. It involves replacing the failed lifter, the lifter guide, and often the camshaft if it has been damaged by the failed lifter's roller. Many owners opt to install an AFM/DFM delete kit to prevent future failures. 🎬 Watch: The permanent fix for GM lifter failure revealed. The repair can cost anywhere from $3,500 to over $7,000 at a dealership.
   Est. part cost: $300-$1500+ for parts, depending on camshaft replacement and if an AFM delete kit is used.
5. Clogged or Faulty Fuel Injector ⚪ Low Probability
   How to confirm: Listen for a consistent clicking sound from the injector. Use a 'noid light' to confirm it's receiving an electrical pulse. Swapping the injector with another cylinder is a definitive test, but more labor-intensive. A user on Tahoe Yukon Forum tried this as part of their diagnosis.
   Typical fix: Replace the faulty fuel injector. Sometimes, using a quality fuel injector cleaner can resolve minor clogs.
   Est. part cost: $50-$150

Rare But Worth Checking

• Low Engine Compression: If ignition and fuel system checks don't reveal the problem, a mechanical issue could be the cause. This could be due to worn piston rings, a bad valve, or a blown head gasket, though these are less common than an AFM lifter failure. A compression test is needed for diagnosis.
• Intake Manifold Gasket Leak: A vacuum leak from a failed intake manifold gasket near the cylinder 2 runner can lean out the air/fuel mixture and cause a misfire. A user on a forum mentioned this as a potential cause.

Diagnosis Steps

1. Read the codes with an OBD-II scanner and note any other codes present, such as P0300 or P050D.
2. Check the freeze frame data to see the engine conditions (RPM, load) when the misfire occurred.
3. Swap the ignition coil from cylinder 2 to another cylinder (e.g., cylinder 4). Clear the codes and see if the misfire code moves to P0304. If it does, replace the coil.
4. If the misfire remains on cylinder 2, swap the spark plug next. Inspect the old plug for signs of wear, oil, or damage. If the plug is the issue, the misfire will stop.
5. Inspect the spark plug wire for cylinder 2 for damage or looseness, per TSB #PIP4819A. Ensure it is fully seated.
6. If ignition components are good, check the fuel injector. Listen for its clicking sound or use a noid light to check for a signal. Swapping the injector is a more involved but definitive test.
7. If the above steps do not identify the cause, perform a compression test on cylinder 2. A user on a forum reported good compression at 150psi, which helped rule out rings/valves. Very low or zero compression points to a mechanical problem.
8. Given the prevalence of AFM issues, if compression is low and a ticking noise is present, suspect a failed lifter. This diagnosis is often confirmed by removing the valve cover to inspect valve train operation. TSB 15-06-01-002L outlines this diagnostic path for technicians.

Parts You'll Likely Need

• Ignition Coil (OEM #ACDelco D510C (Gen 10), ACDelco 12699383 (Gen 11, L83/L86)) — A common failure point causing a single-cylinder misfire. Easy to diagnose by swapping.
  Trusted brands: ACDelco, Delphi
  OEM price range: $60-$127
  Aftermarket price range: $40-$70
• Spark Plug (OEM #ACDelco 41-110 (Iridium for LC9), ACDelco 41-162 (Iridium for L83/L86)) — Spark plugs are a routine maintenance item and a primary cause of misfires.
  Trusted brands: ACDelco Iridium, NGK
  OEM price range: $10-$20
  Aftermarket price range: $5-$15
• AFM Valve Lifter (OEM #ACDelco 12645725 (Common replacement for AFM lifters)) — A significant and known weak point in the 5.3L and 6.2L engines that directly causes single-cylinder misfires when they fail.
  Trusted brands: ACDelco, General Motors, Delphi
  OEM price range: $30-$50 per lifter
  Aftermarket price range: $20-$40 per lifter
• Valve Lifter Guide (OEM #ACDelco 12664915) — GM requires replacing the lifter guides whenever lifters are replaced to ensure proper alignment and prevent rotation, which can cause a repeat failure.
  Trusted brands: ACDelco
  OEM price range: $10-$20
  Aftermarket price range: $5-$15
• Spark Plug Wire Set — Cited in a TSB for causing misfires and can degrade over time.
  Trusted brands: ACDelco, NGK
  OEM price range: $80-$150
  Aftermarket price range: $50-$120

Related Codes That Often Appear With This One

• P0300 — If the misfire is severe or intermittent, the ECM may also log a P0300 (Random/Multiple Cylinder Misfire) code alongside the specific cylinder code. TSBs related to AFM lifter failure often reference P0300 as the primary code.
• P050D — This code for 'Rough Idle Off-Idle' is frequently cited in GM TSBs along with P0300-P0308 codes when lifter failure is the cause.

Technical Service Bulletins (TSBs) & Recalls

• PIP4819A: Mentions that misfire codes can be caused by loose spark plug wires and to inspect and replace them as needed.
• 15-06-01-002L (and previous versions J, K, F, E): A long-running bulletin addressing engine misfires (P0300) and ticking noises caused by failed AFM lifters. It instructs technicians to inspect for collapsed/stuck lifters and check for camshaft damage.
• 19-NA-219: Discusses various engine noises and misfire codes (P0300-P0308), listing a collapsed AFM lifter, worn camshaft lobe, or sticking valve as potential causes.
• 20-NA-038: Referenced in other TSBs for additional information on AFM and DFM usage.

Platform-Specific Known Issues

• Active Fuel Management (AFM) Lifter Failure: This is the most significant vehicle-specific issue. The system is designed to improve fuel economy but the complexity of the lifters makes them a common failure point. A collapsed or stuck lifter will cause a persistent misfire and can lead to camshaft damage if not addressed. TSBs 15-06-01-002E/F/K/L have been repeatedly issued to address this problem.
• Loose Spark Plug Wires: TSB #PIP4819A notes that for 2010 models, misfire codes including P0302 can be caused by spark plug wires that are not fully seated on the spark plug.
• Oil Consumption and Contamination: The AFM system can contribute to increased oil consumption. Low or dirty oil can then exacerbate the problem by causing the delicate hydraulic mechanisms in the AFM lifters to fail.

Mechanic-Grade Diagnostic Values

• Ignition Coil Primary Resistance — expected: 0.4 to 2.0 ohms. Failure: A reading outside this range, especially 0 (short) or infinite (open), indicates a bad coil.
• Ignition Coil Secondary Resistance — expected: 6,000 to 10,000 ohms. Failure: A reading significantly outside this range points to a failure in the secondary windings.
• Fuel Pressure (2010-2014 5.3L LC9) — expected: 55 to 62 PSI. Failure: Pressure below 55 PSI can cause lean conditions and misfires.
• Fuel Rail Pressure (2015+ L83/L86, while cranking) — expected: Approx. 300-400 PSI. Failure: Significantly lower pressure during cranking indicates a problem with the high-pressure fuel system.
• Spark Plug Wire Resistance — expected: Varies by brand; OEM ACDelco may be 8k-9k ohms, while some aftermarket brands are under 1k ohms.. Failure: An infinitely high resistance reading means the wire is open. A reading far outside the norm for the specific brand can also indicate a problem.

Scan Tool Commands That Help

• GDS2 / Tech2: Misfire Data / Misfire Counter — Use this to view live and historical misfire counts for each cylinder. This helps confirm the misfire is isolated to cylinder 2 and determine if it occurs under specific conditions (load, RPM).
• GDS2: Cylinder Deactivation / AFM Test — Used to manually command the AFM system on and off to test lifter and solenoid function. This is a critical step when suspecting an AFM-related failure, even on a non-AFM cylinder, to assess overall system health.
• GDS2: Camshaft Position Actuator Solenoid Valve Cycle — If a no-start condition accompanies the misfire, this command cycles the cam phaser to check if it is stuck, which can affect timing and cause misfire-like symptoms.
• Professional Scan Tool: Cylinder Power Balance Test — This test helps confirm that cylinder 2 is contributing less power than the other cylinders, verifying the misfire before tearing into components.

Wiring & Ground Locations

• G102 — Located at the left rear of the engine.. This is the designated ground point for all 8 ignition coils. A poor connection here can cause weak spark or intermittent misfires on multiple cylinders, which could be initially misdiagnosed as a single cylinder issue.
• Main PCM Ground — Bolted to the top of the engine block, often on the passenger side.. This is a critical ground for the Powertrain Control Module. Corrosion or a loose connection here can cause a wide range of bizarre electrical issues and sensor reading problems, including phantom misfire codes.
• ECM Connector J2, Pin 16 — On the main Engine Control Module connector.. This specific pin is the control circuit for the fuel injector on cylinder 2. When diagnosing a fuel-related P0302, testing for a signal at this pin can confirm if the ECM is commanding the injector to fire.
• Engine Block to Firewall Ground Strap — A braided strap running from the rear of the engine block to the vehicle's firewall.. Ensures the engine has a solid ground reference to the chassis. A broken or corroded strap can lead to erratic behavior from ignition components as they seek a ground path through other means.

Real Owner Repair Stories

• Chevrolet Forum user (2014 Chevrolet Silverado 5.3L (L83 engine family)) — After swapping a salvaged 2015 engine into a 2014 truck, the owner experienced persistent, intermittent misfires on multiple cylinders, including #2, #4, #5, and #8.
  ❌ Tried (didn't work) Replacing individual failing coils with new ones did not fully resolve the issue.
  ✅ What actually fixed it The owner noticed the ignition coils on the original 2014 engine were rectangular, while the salvaged 2015 engine had cylindrical coils. The theory was that the different coil types required different dwell times from the ECM. The final fix was to transfer the remaining original rectangular coils from the old engine to the newly installed engine, which resolved the intermittent misfires.

OEM Part Supersession History

• 12645725 → 12740071 — This is a common replacement part number for the Active Fuel Management (AFM) valve lifter. Part supersessions often indicate a design revision to improve reliability.

Model Year Variations Within This Range

• 2015-2017: The 11th generation Suburban introduced the EcoTec3 engine family (L83, L86), which features Direct Injection. This is a major change from the port injection on 2010-2014 models. It results in different fuel injectors, much higher fuel pressure, and a susceptibility to carbon buildup on intake valves as a potential cause for misfires.
• 2014-2015: The physical shape of ignition coils changed from a rectangular design to a cylindrical/round design. While they may physically fit, they may have different internal specifications (dwell time) and are not always interchangeable without causing intermittent misfires.