P0018 on Buick: How to Diagnose & Fix
Crankshaft/Camshaft Position Correlation - Bank 2 Sensor A
2 Buick models · 4 documented issues · 4 critical · $1,500-$6,500 repair
P0018 on Buick by model: symptoms, diagnosis and fix
Early Enclaves (2008-2012, plus shared Traverse/Acadia/Outlook) with the 3.6L LLT direct-injection V6 share LaCrosse's timing chain stretch and a separate excessive-oil-consumption issue. The PCV system pulls oil into the intake, intake valves carbon up (no port injection to wash them), and the chain wears prematurely from stretched OLM intervals.
Common Symptoms
- cold start rattle
- oil consumption (1 qt/1,000 miles)
- misfire
- rough idle
How to Fix
Timing chain replacement ($2,500-$4,500 with 3-row crossover labor premium). Walnut-blast intake valve carbon at the same time ($300-$500). PCV system update per TSB. Some owners refuse the chain job at this mileage and trade — failure can mean total engine replacement ($6,000+).
Sources for this issue (1)
The 3.6L (and 2.8L) high-feature V6 in 2008-2013 Enclaves is prone to timing chain stretch and worn chain guides/tensioners, sometimes appearing as early as 40,000-60,000 miles. As the chain elongates, valve timing drifts, triggering misfires and a rattle at idle/startup; if a chain jumps a tooth it can bend valves and cause catastrophic engine damage. GM acknowledged the defect (occurring even with regular oil changes) and issued Special Coverage Adjustment #11340C extending the chain warranty to 10 years/120,000 miles on affected engines.
Common Symptoms
- Rattling noise at idle or cold startup
- Check engine light
- Engine misfire / rough running
- Reduced engine power message
- Metal shavings in oil
How to Fix
Replace the timing chains, guides, and tensioners (a full front-of-engine job). If covered under GM Special Coverage #11340C the repair is free up to 10yr/120k mi; otherwise it is an out-of-pocket repair. Keeping oil changes current and using correct-spec oil slows wear.
Sources for this issue (1)
The GM 3.6L V6 (LY7/LLT, and to a lesser extent the early LFX) used in the second-generation LaCrosse is prone to premature timing chain wear and stretch, especially on pre-2012 engines. Worn chains throw off cam-to-crank correlation, setting timing codes and, if neglected, can cause valve-to-piston contact and catastrophic engine damage. The problem is worsened by extended oil-change intervals and a marginal PCV system that accelerates oil contamination.
Common Symptoms
- Metallic rattle or clatter from front of engine for 2-5 seconds on cold start
- Check engine light
- Reduced engine power / limp mode
- Engine ticking or rattling noise
- Rough running or misfire
How to Fix
Replace the timing chains, guides, and tensioners (a full timing set) along with the cam phasers; budget for a labor-intensive front-of-engine teardown. Maintain strict 5,000-mile oil changes with the correct dexos1 oil to prevent recurrence. GM revised chain and tensioner components for later production engines.
Sources for this issue (1)
The GM 3.6L LLT (2007-2011) and LFX (2012+) "High Feature" V6 in LaCrosse, Enclave, Acadia, Traverse, CTS, Cadillac SRX, and many others suffers timing chain stretch typically between 80,000-150,000 miles. Root cause is oil-related — original OLM intervals (up to 12,000 miles) starved the chain of fresh oil. Excessive oil consumption (LLT also has a known consumption issue) accelerates wear.
Common Symptoms
- cold start rattle
- check engine light
- extended cranking
- misfire
- low oil between changes
How to Fix
Full timing chain kit ($2,000-$3,500 incl. labor) — both primary and secondary chains, all tensioners and guides. Switch to 5,000-7,500 mile oil intervals with full-synthetic dexos1 5W-30. LLT engines may also need PCV valve replacement to reduce oil consumption (TSB 10-06-01-007).
Sources for this issue (1)
P0018 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0018 mean on a Buick?
P0018 stands for "Crankshaft/Camshaft Position Correlation - Bank 2 Sensor A." This code means the computer detected that the crankshaft and the Bank 2 'A' (typically intake) camshaft are out of their expected timing relationship. The computer compares the crankshaft and camshaft position sensor signals; they should stay in a fixed correlation as the engine turns. When the Bank 2 camshaft is too far off from the crankshaft, P0018 sets, indicating the valve timing on that bank is misaligned. This can cause rough running, reduced power, hard starting, or a no-start, and in some cases signals timing chain or phaser trouble that warrants prompt attention. On Buick it is documented across 2 models: Enclave, LaCrosse.
What are the most common causes of P0018?
The most common causes of P0018 are: Stretched, worn, or jumped timing chain (Bank 2), Worn or broken timing chain guides/tensioner, Stuck variable valve timing solenoid or phaser, Low or dirty engine oil affecting the phaser, Faulty crankshaft or camshaft position sensor, Damaged reluctor/tone ring, Incorrect timing from prior service, Wiring or connector fault at a cam/crank sensor. The specific cause varies by vehicle.
How much does it cost to fix P0018 on a Buick?
Published repair estimates on Buick range from $1,500 to $6,500 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0018 on a different make?
View P0018 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.