Audi A5 1.8 TFSI Pro Line S common faults.

2011–2017, convertible, petrol, 170 HP.

The fault list covers: CABD, CJEB engine, ML311 transmission.

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5 fault write-ups. 4 important. 5 recalls.

If you know the year, pick it. Faults for other years drop out of the list.

Before you buy

Known faults

4 important faults

expensive4

B8 platform: the actuator motor of the electric parking brake

expensive

A small electric motor built into the rear brake calipers applies the parking brake. This is a known weak point of the B8 platform (A4 B8, A5 8T, Q5 8R, allroad B8): moisture and road salt get into the motor housing, the electronics corrode, and the gears seize. The symptom is a parking brake that will not apply or will not release, with a fault message.

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Two things are worth knowing about it. First, the system is sensitive to voltage: a weak battery dropping below 12.2 V can trigger an intermittent parking brake fault on its own, especially in the cold. In that case it is not the brake that needs replacing. Second, servicing the rear brake requires putting the caliper into service mode with a diagnostic tool; forcing the piston back by hand destroys the actuator itself.

above 50,000 km

What to check

Apply and release the parking brake several times in a row: it must work evenly and without a fault in both directions
Stop the car on a slope on the parking brake alone: it has to hold
After switching the ignition on, check for a parking brake or hill hold fault message

2 more steps in the write-up

Convertible: wet fabric roof, roof that stops halfway

expensive

The drains of the fabric roof block up with leaves and dust, the seals wear out over the years, and water runs into the rear footwell, behind the side trim and into the boot. The roof electronics and the switches fail too, and then the roof stops halfway or does not start at all. Soaked connectors are ruined, the roof repair costs parts and labour, and if it stops halfway in the rain the cabin gets soaked.

What to check

Open and close the roof fully, at least twice: it must not stop halfway or bind
With the roof open, find the drain openings where the roof folds down: they should be clear
Feel the rear footwell and the side trim under the carpet

2 more steps in the write-up

EA888 (1.8 / 2.0 TSI): water pump and thermostat housing leak

expensive

The combined housing of the water pump and the thermostat is plastic, and it is bolted directly to the hot engine block. The many heat and cool cycles warp it, it becomes brittle, and then it develops a hairline crack: the fault is almost always the housing, not the pump itself. The signs are slowly disappearing coolant with no visible puddle, the coolant level light, a sweet smell from the engine bay, and later a pink stain under the car. The repair means replacing the pump and the housing together, and the intake manifold has to come off for it: 4 to 6 hours of work. It shows up on model years 2015 to 2025.

What to check

Check the level in the expansion tank, and ask whether it needs topping up
With a cold engine, smell the engine bay: a sweet smell means a coolant leak
Shine a light under the intake manifold, on the right side of the engine: dried or pinkish deposits

2 more steps in the write-up

FSI direct injection: intake valve coking

expensive

With direct injection the fuel does not wash the intake valves: the petrol goes into the cylinder, not behind the valve. The oil mist and soot arriving through the EGR and the crankcase ventilation therefore build up on the valve stem and head, and from 80,000 to 100,000 km they restrict the flow. Symptoms are hesitation, loss of power, a rough cold start and misfire. It is not a part failure: it is a consequence of the design, and therefore it comes back. Cleaning (walnut or dry ice blasting) helps for a few tens of thousands of kilometres.

What to check

After a cold start watch the idle: rough running and shaking point to coked valves
Under load at low revs watch for hesitation
With a code reader look for per cylinder misfire (P0300 to P0304)

1 more steps in the write-up

cheap repair1

Sticking fuel flap on the Sportback and the convertible

cheap repair

On the Sportback and the convertible the fuel flap often sticks, it does not open from the button or it stays open, and this shows up on cars built between 2010 and 2016. The part is cheap, but you still cannot refuel while the flap stays shut, and on a test drive it takes half a minute to check.

What to check

Open and close the fuel flap three times
Try it with the central locking locked and unlocked too
Look for signs of prying around the edge of the flap

Official recall5 recallsShow

The manufacturer fixes these for free at a franchised dealer. Ask with the VIN whether it was done.

A12/0382/19Safety recallFireno date · EU Safety Gate

In certain vehicles, fuel can leak onto the engine fuel rail. Fuel leakage close to a source of ignition may increase the risk of the vehicle catching fire.