P0016 on Audi: How to Diagnose & Fix

The Q5 2.0T uses the EA888 engine with the well-documented timing chain tensioner weakness. Audi's timing chain/tensioner limited warranty extension (Warranty Key U35) covered only 2011-2012 Q5 models with the 2.0L EA888 engine. The tensioner loses pressure overnight, allowing chain slack on cold starts that progressively worsens until the chain jumps timing.

Early Audi A1 8X petrol cars fitted with the EA111 1.2 TFSI (CBZA/CBZB) and 1.4 TFSI (CAXA/CTHG/CAVG) engines suffer from a weak timing chain tensioner that loses hydraulic pressure, allowing the chain to go slack and stretch. Combined with worn plastic chain guides, the camshaft timing drifts out of correlation with the crankshaft. If the chain jumps a tooth (commonly on cold start before oil pressure builds) the pistons can strike the valves, destroying the engine. The chain sits behind the timing cover at the crankshaft-pulley end of the engine, and replacement requires removing the pulley, timing cover and sump, making it labour-intensive.

The C6 A6 with the 3.2L V6 and 4.2L V8 engines suffers from timing chain tensioner failures due to wear over time. Audi designates the chains and tensioners as "lifetime" parts requiring no maintenance, but they fail as early as 80,000-120,000 miles. The 3.2L engine has 4 chains, 3 tensioners, and several guides—all prone to wear. A loud rattling or clicking noise on cold start from the upper rear of the engine is the classic symptom of failing tensioners. If ignored, the timing chain can jump or break, causing catastrophic valve-to-piston contact and complete engine destruction. The transmission must be removed for full access, making this a labor-intensive repair. AudiWorld forums report low-mileage cars with stretched chains due to the design flaw.

The B6/B7 S4's 4.2L V8 (BBK/BHF) drives its timing chains from the BACK of the engine, against the firewall. What owners call "timing chain failure" is really the plastic chain guides, the chain tensioners and the two camshaft adjusters wearing out and disintegrating. Forum documentation shows plastic guide fragments sitting on the chains, with cases reported at roughly 100k-112k miles. Because the chain drive is at the rear, there is no way in from the front of the car: the engine (or at minimum the whole drivetrain assembly on a subframe drop) must come out. This is the single defining failure of this generation and is NOT shared with the B5 2.7T (belt-driven) or the B8/B9 V6s. Left alone, a snapped guide lets the chain jump timing and destroys valves and pistons on an interference engine.

The B8/B8.5 A5 with the 2.0 TFSI engine (2008-2016) suffers from premature timing chain tensioner failure, identical to the A4 and A6. The tensioners wear out between 60,000-120,000 miles, causing the timing chain to stretch and rattle. A loud rattling noise on cold start from the front of the engine is the classic warning sign. If ignored, the timing chain can jump timing or break, causing catastrophic valve-to-piston contact and destroying the engine. Early B8 models (2008-2012) are more prone to failure than later B8.5 models (2013-2016). A5OC forum members report many failures under 100,000 miles, with some owners experiencing complete engine destruction. The repair requires removing the front of the engine and costs $2,000-$5,000. Some owners report oil consumption issues leading to accelerated tensioner wear.

The D3-generation S8 uses the 5.2L FSI V10 (shared lineage with the Lamborghini Gallardo/R8 V10). Its timing is driven by chains with plastic guides and hydraulic tensioners located at the rear of the engine. Over time and with deferred oil changes, the tensioners and guides wear, producing a rattle on cold startup that can persist. If a guide breaks or the chain skips, valve-to-piston contact can cause catastrophic engine damage. Access is poor (rear of the V10), making this an engine-out-level job and one of the most expensive risks on the D3 S8.

The first-generation D2 S8 uses the 4.2L 40-valve V8, an interference engine driven by a timing belt (intake cams) plus chains (exhaust cams). The belt is a maintenance-critical, age-and-mileage-limited item: Audi specifies replacement around 105k miles, but many specialists recommend shorter intervals (or every ~6 years) because failure is catastrophic — a snapped belt lets valves and pistons collide. Associated tensioners, rollers, and the water pump are commonly replaced together. On these older cars the chain tensioners on the exhaust side can also wear and rattle. This is the single most important service to verify on any D2 S8 purchase.

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.

Owners of three-cylinder 1.0 TFSI and four-cylinder 1.4 TFSI Q2s have reported the toothed cambelt snapping well before Audi's stated 5-year / ~75,000-mile replacement interval, in several documented cases between roughly 39,000 and 49,000 km/miles, with full service history. Because these are interference engines, a snapped belt causes the valves to collide with the pistons, leading to catastrophic internal damage and frequently an entire engine replacement. Contributing factors cited by owners and forum moderators include the extra start/stop cyclical loading on the belt and frequent short journeys, plus belt tensioner/bolt loosening. Audi typically offered only partial goodwill rather than full coverage out of warranty.