P0011 on 2020-2025 Buick Encore GX: Causes and Fixes for Camshaft Timing Over-Advanced

What's Unique About the 2020-2025 Buick ENCORE GX

The Buick Encore GX and its platform-mate, the Chevrolet Trailblazer, use small displacement turbocharged three-cylinder engines (1.2L LIH or 1.3L L3T). For these specific vehicles, General Motors has issued multiple Technical Service Bulletins (TSBs) that point directly to known issues causing P0011. These include TSB #A202304840-02 and #20-NA-120, which address a condition where the camshaft actuator's center bolt could stick or bind internally on 2020-2021 models with the 1.3L engine. Another TSB, #PIP6082, highlights the potential for debris to collect in the camshaft actuators. Both issues can disrupt normal VVT operation and trigger this code.

Diagnostic Flowchart

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

Symptoms You May Notice

• Check Engine Light illuminated
• Rough idle or engine running rough
• Unstable engine RPM at idle
• Engine surge or misfire
• Reduced engine power
• Difficulty starting the engine
• Poor fuel economy
• Engine stalling
• Sluggish or jerky acceleration

Most Likely Causes

1. Low or Dirty Engine Oil 🔴 High Probability The VVT system is entirely dependent on clean engine oil at the correct pressure to function. Sludge from extended oil change intervals, low levels, or incorrect oil viscosity will prevent the cam phasers from operating correctly, a common issue in many VVT-equipped engines.
   How to confirm: Check the engine oil dipstick for proper level and inspect the oil's color and consistency. If it's low, black, or sludgy, it needs to be changed.
   Typical fix: Perform an oil and filter change using the manufacturer-specified full synthetic DEXOS-approved oil. Clear codes and see if P0011 returns.
   Est. part cost: $40-$80
2. Failed Intake Camshaft Position Actuator Solenoid (VVT Solenoid) 🔴 High Probability This solenoid is a common failure point in VVT systems. It can get clogged with debris from the oil or fail electronically. TSB #A202304840 02 and TSB #20-NA-120 specifically mention issues with the camshaft actuator oil control valve (OCV) for the 2020-2021 model years.
   How to confirm: Swap the intake and exhaust solenoids (they are identical parts) and see if the code changes to P0014 (exhaust camshaft). If it does, the solenoid is bad. A capable scan tool can also command the solenoid to check for response, and a multimeter can be used to check its internal resistance.
   Typical fix: Replace the Bank 1 intake camshaft position actuator solenoid. 🎬 See this walkthrough on how to replace a VVT solenoid Many technicians recommend replacing both intake and exhaust solenoids at the same time.
   Est. part cost: $30-$70
3. Debris in Camshaft Actuators 🟡 Medium Probability TSB #PIP6082 specifically calls out the possibility of an engine surge or misfire with a P0011 code due to potential debris in the cam actuators. This can happen if oil change intervals are extended, leading to sludge.
   How to confirm: This is difficult to confirm without disassembly. Inspecting the old solenoid's screens for metallic debris upon removal can be a strong clue. This cause is usually suspected after an oil change and solenoid replacement don't fix the issue.
   Typical fix: Requires cleaning the camshaft actuator oil passages and potentially replacing the camshaft actuator (phaser). In some cases, an engine flush during an oil change has resolved the issue.
   Est. part cost: $150-$300
4. Sticking/Binding Camshaft Actuator Bolt ⚪ Low Probability TSB #A202304840 02 and TSB #20-NA-120 for the 2020-2021 Encore GX and 2021 Trailblazer note that the camshaft actuator oil control valve (OCV) center bolt could stick or bind internally, causing P0011.
   How to confirm: This condition was subject to a specific service campaign for vehicles in dealer inventory. A GM dealer can check the vehicle's history. The dealer inspection procedure involved a specific engine warm-up and revving sequence to see if the code would set.
   Typical fix: If the vehicle failed the inspection outlined in the TSB, the dealer replaces the camshaft position actuator solenoid bolts or, in some cases, the bolt sleeve.
   Est. part cost: $10-$20

Rare But Worth Checking

• Stretched Timing Chain: While less common on newer vehicles, a stretched timing chain can alter the cam/crank correlation enough to set this code. This is a major repair and is often accompanied by rattling noises on startup. Some owners have reported timing chain issues on the 1.2L engine.
• Faulty Camshaft Position Sensor: It's rare for the sensor itself to fail in a way that causes an over-advanced code. The problem is more often with the mechanical control of the timing, not the sensor's reading of it. A faulty sensor would likely trigger other codes as well.
• Faulty Engine Control Module (ECM) or Main Relay: In very rare cases, a failing ECM could misinterpret sensor data and set a false code. A faulty main relay can also cause a variety of engine performance issues, though it's not a primary cause of P0011.

Diagnosis Steps

1. Check the engine oil level and condition. 🎬 Watch this before taking your Buick to a mechanic Top up or perform an oil and filter change if necessary, using the correct DEXOS-approved oil. This is the most common and cheapest fix.
2. Scan for any other DTCs. The presence of codes like P0014, P0300, P0016, or P0017 can help pinpoint the root cause.
3. Inspect the wiring and connector for the intake camshaft position actuator solenoid for damage, corrosion, or oil contamination.
4. The intake and exhaust solenoids are identical parts. Swap their positions. Clear the codes and drive the vehicle. If the code changes to P0014, the solenoid you moved to the exhaust position is faulty and needs replacement.
5. If a new solenoid does not fix the issue, inspect the old solenoid's screens for fine metal debris. If debris is present, it may indicate a larger issue like a failing cam phaser or debris in oil passages, as noted in TSB #PIP6082. Consider performing an engine flush.
6. If the vehicle is a 2020-2021 model, consult a GM dealer regarding TSB #A202304840 02 and #20-NA-120 for the sticking actuator bolt. A dealer can check if this service action is open for your VIN.

Parts You'll Likely Need

• Intake Camshaft Position Actuator Solenoid (OEM #12694738) — This is the most common mechanical part to fail, either by getting clogged with debris or failing electronically. It directly controls the oil flow that adjusts the camshaft's timing. This part number is generally associated with the 1.3L L3T engine.
  Trusted brands: ACDelco (GM Original Equipment)
  OEM price range: $40-$70
  Aftermarket price range: $25-$50
• Exhaust Camshaft Position Actuator Solenoid (OEM #12694738) — This part is identical to the intake solenoid and is useful for the diagnostic swap test. If swapping the solenoids causes the code to change to P0014, you have confirmed the original intake solenoid was faulty. It is often recommended to replace both at the same time.
  Trusted brands: ACDelco (GM Original Equipment)
  OEM price range: $40-$70
  Aftermarket price range: $25-$50
• Engine Oil and Filter — Low or dirty oil is a primary cause of all VVT system faults. An oil change is the first and most crucial step in diagnosis and repair.
  Trusted brands: ACDelco
  OEM price range: $50-$90
  Aftermarket price range: $40-$70

Related Codes That Often Appear With This One

• P0014 — This is the corresponding code for the exhaust camshaft. TSBs #A202304840 02, #20-NA-120, and #PIP6082 all mention P0011 and P0014 occurring together, often pointing to a systemic issue like oil pressure/quality or a binding bolt affecting both actuators.
• P0300 — This indicates a random or multiple cylinder misfire. Incorrect camshaft timing disrupts the engine's combustion cycle, leading to misfires. TSB #PIP6082 directly links P0011 with P0300.
• P0016 / P0017 — These codes indicate a crankshaft/camshaft correlation error. If the timing is sufficiently advanced, it can trigger these more severe timing correlation codes. TSBs #PIP6082 and #20-NA-120 also list these as potential companion codes.

Technical Service Bulletins (TSBs) & Recalls

• PIP6082: Potential for debris in cam actuators.
• A202304840-02 / 20-NA-120: Sticking or binding camshaft actuator oil control valve center bolt.

Platform-Specific Known Issues

• TSB #PIP6082: Mentions that an engine surge or misfire accompanied by DTC P0011 can be due to debris in the camshaft actuators.
• TSB #A202304840 02 / #20-NA-120: Notes that on certain 2020-2021 models with the 1.3L L3T engine, the camshaft actuator oil control valve (OCV) center bolt could stick or bind, causing P0011 or P0014, a rough running engine, and reduced power.

Mechanic-Grade Diagnostic Values

• Camshaft Position Actuator Solenoid Resistance — expected: 5 - 12 Ohms. Failure: A reading outside this range (significantly lower or infinite) indicates a failed solenoid coil.
• Camshaft Position Desired vs. Actual Angle (Scan Tool Data) — expected: Actual angle should closely track the desired angle commanded by the ECM.. Failure: A large, persistent deviation between the desired and actual angle, especially when the ECM is commanding a change and the actual value remains static (e.g., stuck at 28 degrees), indicates a mechanical or hydraulic fault in the VVT system.

Scan Tool Commands That Help

• GM GDS2: Camshaft Position Actuator Control — Under 'Engine Control Module -> Control Functions', this bidirectional test allows a technician to command the intake and exhaust VVT solenoids on and off to verify their mechanical operation. A change in engine idle should be observed if the solenoid and phaser are working.
• GM GDS2: Crankshaft Position Variation Learn — This procedure, sometimes called a 'cam/crank relearn', should be performed after replacing a camshaft position sensor, crankshaft position sensor, or any major timing component to allow the ECM to learn the new components' precise positions and avoid false timing codes.

Wiring & Ground Locations

• G103 — Located on the cowl (firewall) in the engine compartment, typically above the brake booster.. This is a primary ground point for the Body Control Module (BCM) and Engine Control Module (ECM). A poor connection here can cause a wide range of erratic electronic faults and incorrect sensor readings, potentially leading to false P0011 codes.
• G101 — Located at the lower front of the engine block.. This is another main ground for the Engine Control Module (ECM) and Transmission Control Module (TCM). A loose or corroded connection here can disrupt ECM operation and cause various engine management codes.
• Camshaft Position Sensor Connector (1.2L Engine) — On the 1.2L LIH engine, the tachometer signal wire can be found at the camshaft position sensor.. An installation guide for a remote starter identifies the tach signal wire as Yellow/Violet at Pin 3 of the black 3-pin connector. While not directly for the VVT solenoid, it provides a specific, confirmed wiring detail for a related component in the system.

Real Owner Repair Stories

• YouTube user comment (Similar GM VVT system) — P0011 code returned one week after an oil change, and again 100 miles after a second oil change.
  ❌ Tried (didn't work) Two separate oil changes only fixed the problem temporarily.
  ✅ What actually fixed it The user removed the VVT solenoids, cleaned them with carburetor cleaner, performed an engine flush, and added fresh oil. The code did not return after 1,000 miles of driving, indicating the root cause was sludge or debris that the oil changes alone could not clear.
• Reddit user in r/MechanicAdvice (2016 Chevy Cruze (similar VVT system)) — P0011 code appeared 3 days after an oil change, with some engine sluggishness.
  ❌ Tried (didn't work) Replacing the intake VVT solenoid did not fix the issue; the code returned.
  ✅ What actually fixed it The problem was resolved by using an engine cleaner/flush product during the next oil change, which removed sludge buildup that was causing the new solenoid to stick.

OEM Part Supersession History

• 12694738 → N/A - Engine Specific — Part number appears to be specific to the 1.3L L3T engine.
  Heads up: This part number is likely for the 1.3L engine. Do not confuse with the part for the 1.2L engine.
• 55595279 → N/A - Engine Specific — Part number is specific to the 1.2L LIH engine.
  Heads up: Multiple parts vendors list this solenoid specifically for the 1.2L engine in the 2020-2025 Encore GX and Trailblazer.

Model Year Variations Within This Range

• 2020-2021: Models with the 1.3L L3T engine may be subject to TSB #A202304840-02 / #20-NA-120 for a sticking camshaft actuator oil control valve (OCV) center bolt. The original part used a plastic-overmolded sleeve which could bind. The fix involves replacing it with an updated steel sleeve kit.
• 2024-2025: The Encore GX received a significant exterior and interior refresh for the 2024 model year, including a new 'Virtual Cockpit' dashboard. However, the 1.2L and 1.3L engine and transmission options remained the same, so the mechanical causes and fixes for P0011 are not expected to differ from earlier years.