P0018 on Audi: How to Diagnose & Fix
Crankshaft/Camshaft Position Correlation - Bank 2 Sensor A
1 Audi model · 1 documented issue · 1 critical · $4,500-$9,000 repair
P0018 on Audi by model: symptoms, diagnosis and fix
The 4.2L FSI V8 (BAR) in the first-generation Q7 4L uses a rear-mounted timing chain drive with plastic chain guides and hydraulic tensioners. The guides embrittle and the tensioners lose their ability to take up slack, especially on engines run past their oil-change interval or on short trips where sludge forms. Owners first hear a brief rattle at cold start that grows into a constant rattle or whine, and eventually the chain jumps a tooth and sets cam/crank correlation faults. Because the chain drive is at the back of the engine, the correct repair requires pulling the engine (or engine and transmission) out of the vehicle - which is why this failure so often totals an otherwise good high-mileage Q7.
Common Symptoms
- Rattle from the rear of the engine on cold start
- Rattle that persists after warm-up on higher-mileage engines
- Check engine light with camshaft position correlation faults
- Rough running or misfire after the chain jumps a tooth
- No-start or engine damage if the chain skips under load
How to Fix
At the first sign of persistent cold-start rattle, scan for cam/crank correlation codes and have the chain stretch measured. The proper repair is engine-out replacement of the timing chains, all plastic guides, and both hydraulic tensioners with the latest revised parts, plus new chain-drive seals. Prevention: 5,000-mile full-synthetic oil changes rather than the long factory interval, and never top up with the wrong grade.
Sources for this issue (2)
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 Audi?
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 Audi it is documented across 1 model: Q7.
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 Audi?
Published repair estimates on Audi range from $4,500 to $9,000 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.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.