P0011 on 2018-2019 Buick Enclave: Causes, Fixes, and ECM Reprogram TSB

What's Unique About the 2018-2019 Buick ENCLAVE

For the 2018-2019 Enclave and its platform mates with the 3.6L LGX engine (like the Chevy Traverse, Cadillac XT5, and Buick LaCrosse), this code is uniquely and strongly tied to the vehicle's auto start/stop system. Multiple Technical Service Bulletins (TSBs) issued by GM confirm that a software anomaly can cause this code to set, often with P0014, P0021, and P0024, leading to rough running, reduced power, or stalling immediately after an engine auto-restart. In many of these documented cases, the fix is not a mechanical part replacement but a simple ECM software update performed by a dealer.

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
• Engine runs rough, especially at idle or after an auto-start event.
• Reduced engine power message on the Driver Information Center (DIC).
• Engine stalling, particularly when the vehicle is stopped after an auto-restart.
• Transmission shudder.
• Difficulty starting the engine.
• Poor fuel economy.
• Engine rattling noises (can indicate a more serious timing chain or phaser issue).

Most Likely Causes

1. Engine Control Module (ECM) Software Update Needed 🔴 High Probability GM issued TSB #N192266190 specifically for 2018-2019 models with the 3.6L LGX engine. A software anomaly causes the ECM to misreport cam positions after an auto start/stop event, leading to drivability issues and setting codes P0011, P0014, P0021, and P0024.
   How to confirm: A GM dealer can check the vehicle's VIN in the Global Warranty Management system to see if service update N192266190 is marked as "open". This confirms the update has not been performed.
   Typical fix: Dealer reprograms the Engine Control Module (ECM) with updated software via SPS (Service Programming System). No parts are required for this specific fix.
   Est. part cost: $0-$250
2. Low or Dirty Engine Oil 🔴 High Probability The VVT system is entirely dependent on oil pressure to function. If the oil is low, contaminated with fuel or debris, or the wrong viscosity (GM specifies full synthetic DEXOS oil), the camshaft actuator solenoids cannot adjust cam timing correctly.
   How to confirm: Check the engine oil level on the dipstick. The oil should be translucent and amber-colored, not black, thick, or gritty. Ensure the correct oil is being used per the owner's manual.
   Typical fix: Perform an oil and filter change using the manufacturer-specified oil and filter. Clear codes and test drive.
   Est. part cost: $50-$100
3. Faulty Intake Camshaft Position Actuator Solenoid (Bank 1) 🟡 Medium Probability This solenoid controls oil flow to the phaser. Its internal screens can get clogged with sludge, or the solenoid can fail electronically. Some owners report oil leaking through the solenoid body and into the electrical connector, causing a poor connection and failure.
   How to confirm: A mechanic can command the solenoid with a scan tool to check response. Visually inspect the solenoid's connector for oil contamination. It can also be removed and inspected for clogged screens or tested for resistance (typically 8-13 ohms).
   Typical fix: Replace the Bank 1 intake camshaft position actuator solenoid and clean any oil out of the harness connector. 🎬 Watch: A helpful walkthrough of the actuator solenoid valve replacement.
   Est. part cost: $40-$80

Rare But Worth Checking

• Stretched Timing Chain: While less common on the newer LGX engine compared to its predecessor (the LLT), a stretched timing chain can cause camshaft/crankshaft correlation errors. This is usually accompanied by rattling noises from the front of the engine, especially on cold starts.
• Faulty Camshaft Phaser: The phaser is the mechanical gear that actually rotates the camshaft. It can fail internally, getting stuck in an advanced position. This is a more complex and expensive repair, often requiring removal of the timing cover.
• Stuck or Collapsed Timing Chain Tensioner: TSB PIP5652A notes that for some GM engines, a rattle noise accompanied by codes like P0011 can be caused by a stuck or collapsed timing chain tensioner. This can cause enough slack to affect cam timing.

Diagnosis Steps

1. Check the engine oil level and condition. If it is low, dirty, or overdue for a change, perform an oil and filter change with the correct full synthetic DEXOS oil. Clear the codes and see if the problem returns.
2. Contact a GM dealership with your VIN and ask if Service Update #N192266190 is open for your vehicle. An ECM reprogram is the specific fix for the auto start/stop issue and may be covered under warranty.
3. Inspect the wiring and connector for the Bank 1 intake camshaft position actuator solenoid (on the firewall-side cylinder head). Check for oil contamination inside the electrical connector, which indicates a leaking solenoid that needs replacement.
4. Using a capable scan tool, monitor the desired vs. actual camshaft position angles for Bank 1 intake. A 'sticky' solenoid may show the actual angle lagging the desired angle, then suddenly overshooting it.
5. Test the Bank 1 intake camshaft position actuator solenoid. This can be done by commanding it with a scan tool or by removing it, cleaning it, and applying 12v to check for mechanical operation. 🎬 See this video for a step-by-step VVT solenoid diagnostic guide. Resistance should be between 8-13 ohms.
6. If the solenoid is functional and the software is up to date, the issue may be with the camshaft phaser or, in rare cases, the timing chain itself. Listen for engine rattles. These are more advanced diagnostics best left to a professional.

Parts You'll Likely Need

• Intake Camshaft Position Actuator Solenoid (VVT Solenoid) (OEM #12655420) — This solenoid is a common failure point that directly controls camshaft timing. It can become clogged with sludge or fail electronically, leading to timing errors. The original part 12655420 has been superseded by part number 12679099. 🎬 Watch: How to replace the VVT solenoid on the LGX engine.
  Trusted brands: ACDelco
  OEM price range: $45-$80
  Aftermarket price range: $30-$60

Related Codes That Often Appear With This One

• P0014 — This is the code for the exhaust camshaft ('B') on the same bank (Bank 1). Seeing them together points to an issue affecting the entire cylinder head, like oil flow or the TSB-related software problem.
• P0021 — This is the equivalent 'over-advanced' code for Bank 2 (front bank). Seeing P0011 and P0021 together strongly suggests a systemic issue like low oil pressure or the ECM software glitch mentioned in TSBs.
• P0024 — This is the code for the exhaust camshaft on Bank 2. All four codes (P0011, P0014, P0021, P0024) appearing together is a classic symptom of the ECM software issue described in TSB #N192266190.

Technical Service Bulletins (TSBs) & Recalls

• N192266190: Addresses rough running, reduced power, or stalling after a stop/start event, setting P0011/P0014/P0021/P0024. Fix is an ECM reprogram. This TSB applies to the Enclave, Traverse, XT5, and LaCrosse.
• PIP5568E: An earlier bulletin noting an ongoing investigation into this group of DTCs setting together, caused by a software anomaly where the ECM reports cam positions as '0' after a restart.
• 17-NA-317: Mentions MIL illumination and drivability concerns like transmission shudder and low idle after an Auto Start event, with P0011 being one of the potential codes.
• PIP5652A: Discusses a rattle noise from the front of the engine, with or without codes like P0011, potentially caused by a stuck or collapsed timing chain tensioner.

Platform-Specific Known Issues

• A well-documented issue covered by GM Technical Service Bulletin #N192266190 involves the engine running rough, stalling, or showing reduced power after an auto-start event. This can set codes P0011, P0014, P0021, and P0024. The official fix is to reprogram the Engine Control Module (ECM).
• An owner complaint (NHTSA ODI #11221573) on a 2018 model confirms the simultaneous setting of codes P0011, P0014, P0021, and P0024, corroborating the symptoms described in the TSBs.
• A user on the BobIsTheOilGuy forums noted that for the LGX/LGZ engine family, the VVT solenoids are one of the most common components to fail and require replacement, along with the thermostat.

Mechanic-Grade Diagnostic Values

• Camshaft Position Actuator Solenoid (VVT Solenoid) Resistance — expected: 8 to 13 Ohms. Failure: A reading outside this range, or an open/short circuit, indicates a faulty solenoid.
• Camshaft Position Sensor Voltage (Key On, Engine Off) — expected: Power Wire: ~12V (Battery Voltage); Signal Wire: ~5V; Ground Wire: <10 ohms to chassis ground.. Failure: Missing or incorrect voltage on power/signal wires, or high resistance on the ground circuit, points to a wiring or ECM issue, not a bad sensor.
• Scan Tool 'Camshaft Position Variance' PID — expected: A small, stable value near 0 degrees at idle.. Failure: A large variance, or a value that repeatedly climbs and then suddenly drops (sawtooth pattern on a graph), indicates a sticking VVT solenoid or phaser.

Scan Tool Commands That Help

• GM GDS2 / Tech 2: Camshaft Position Actuator Control — This is a bidirectional test used to command the solenoid on and off while the engine is running to verify its mechanical response. A change in engine idle should be observed, confirming the solenoid is not seized.
• GM SPS (Service Programming System): Engine Control Module Reprogramming — This is the specific fix outlined in TSB #N192266190 to resolve the software anomaly that causes P0011 and other codes after an auto start/stop event.

Wiring & Ground Locations

• G103 — On the left frame rail, located underneath the Starter Generator Control Module (SGCM) bracket. The cable runs from the transmission housing to this ground point.. A poor connection at this major ground point can cause a wide range of electrical issues, including no-start or stalling conditions and erratic ECM/TCM behavior that could potentially trigger false timing codes.
• Bank 1 Intake VVT Solenoid Connector — On the Bank 1 (firewall side) cylinder head valve cover, connected to the intake camshaft position actuator solenoid.. This is the direct electrical connection for the component. It should be inspected for oil contamination (indicating a leaking solenoid) and its two pins can be used to measure the solenoid's resistance.
• ECM Connector X1 — On the Engine Control Module (ECM), typically in the engine compartment. On related GM V6 engines, this connector houses the control circuits for the VVT solenoids.. A technician may need to probe specific pins at this connector to perform pin-out tests for continuity or shorts in the wiring between the ECM and the VVT solenoid.

OEM Part Supersession History

• 12655420 → 12679099 — Part revision or replacement by manufacturer. Reasons are not typically published but often involve improvements in materials or design.
  Heads up: While they should be interchangeable, it is always best practice to use the latest superseded part number (12679099) when replacing.

Model Year Variations Within This Range

• 2018-2019: These specific model years are subject to TSB #N192266190, which identifies a software glitch related to the auto start/stop system as a primary cause for P0011 (often with P0014, P0021, P0024). The fix is a dealer-performed ECM reprogram. Models outside this range are less likely to have this specific software-related cause.