Most common 2018 Audi A4 problems
Share of the 45 complaints; one complaint can involve more than one system. "~" is the median mileage when the problem started.
Audi A4 complaints by model year
Best A4 years: 2011, 2016, 2012. Years to avoid: 2020, 2008, 1998, 2006, 1999. Compare all years →
2018 Audi A4 recalls (1)
Air bags › Sensor › Occupant classification › Front passenger
Volkswagen Group of America, Inc. (Audi) is recalling certain 2017-2020 A4 Allroad, A4 Sedan, 2018-2019 RS5 Coupe, 2019 RS5 Sportback, 2018-2020 A5 Cabriolet, A5 Coupe, A5 Sportback, S4 Sedan, S5 Cabriolet, S5 Coupe, and Audi S5 Sportback vehicles.
Remedy: Dealers will replace the connecting cable and either the heating mat or entire seat cover, free of charge. Owner notification letters were mailed January 7, 2022.
What 2018 Audi A4 owners say
Electrical system
A vehicle diagnostic scan dated 04/15/2026 at approximately 88,502 miles showed a stored transmission electronics fault: P084100, described as "Transmission fluid pressure sensor/switch A range/performance," with status listed as passive/sporadic. This indicates a transmission / powertrain control concern involving the transmission fluid pressure sensor, transmission electronics, wiring, control logic, pressure monitoring, or related powertrain components. The vehicle also has prior transmission/powertrain history, including a March 2023 transmission-pan-gasket concern documented in service records, so this later transmission electronics fault is being reported in that broader powertrain context. …
A vehicle diagnostic scan dated 04/15/2026 showed electrical communication faults involving vehicle control modules. The scan showed U014100, described as "Lost Communication With Body Control Module 'A'," with status listed as passive/sporadic. The scan also showed U112100, described as "Data bus message missing," with status listed as active/static. This is being reported as a safety concern because body-control module, gateway, and data-bus communication faults can affect vehicle electrical functions, warning systems, access/locking systems, lighting or body-control functions, driver information, and other vehicle systems that rely on module communication. The concern is especially important because the vehicle has had multiple intermittent electrical/body-control symptoms, including fuel-door/tank-flap electrical faults and other reported intermittent vehicle electrical concerns. …
Body & structure
A vehicle diagnostic scan dated 04/15/2026 showed electrical communication faults involving vehicle control modules. The scan showed U014100, described as "Lost Communication With Body Control Module 'A'," with status listed as passive/sporadic. The scan also showed U112100, described as "Data bus message missing," with status listed as active/static. This is being reported as a safety concern because body-control module, gateway, and data-bus communication faults can affect vehicle electrical functions, warning systems, access/locking systems, lighting or body-control functions, driver information, and other vehicle systems that rely on module communication. The concern is especially important because the vehicle has had multiple intermittent electrical/body-control symptoms, including fuel-door/tank-flap electrical faults and other reported intermittent vehicle electrical concerns. …
The vehicle has a recurring interior rattle / loose-trim concern involving interior panels, trim, speaker/subwoofer area, rear shelf, dashboard area, or related mounting components. The noise is not merely a comfort concern if it is caused by a loose component, fastener, grille, panel, or speaker housing that may move, worsen, detach, or distract the driver. This is being reported as a safety concern because loose interior trim or components can distract the driver, interfere with normal vehicle use, create uncertainty about whether a component is secured, and may indicate improper fastening, panel fitment, speaker/subwoofer mounting, or body/electrical component installation issues. If the affected trim is near safety-system areas, it should be inspected to confirm it does not affect wiring, restraint-system areas, visibility, or safe vehicle operation. …
Engine & cooling
The contact owned a 2018 Audi A4. The contact stated that while driving at an undisclosed speed, there was fluid leaking from the front of the vehicle. No warning lights were illuminated. The contact also stated that while the vehicle was parked, there was a puddle of fluid leaking from the front of the vehicle. The vehicle was taken to an independent mechanic, where it was diagnosed and it was determined that the water pump had failed and needed to be replaced. The vehicle was not repaired. The dealer was contacted. The vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 92,000.
The vehicle displayed a low coolant warning and the coolant reservoir was low. Audi dealer service records dated on or about 02/14/2025 document the concern as: "client states low coolant warning was on, coolant reservoir is low, diagnose and advise." The dealer performed coolant-related work involving the thermostat gasket / coolant hoses or connections to the coolant reservoir, ran the vehicle to operating temperature, and rechecked. The concern is being reported because the coolant loss/refill issue continued or remained unresolved afterward. The exact source of coolant loss is unknown, but it may involve the water pump, thermostat, coolant reservoir, coolant hoses/pipes, pressure loss, internal coolant leak, or coolant loss that evaporates before leaving visible residue. …
2018 Audi A4 engines & fuel economy
| Engine | Transmission | Drive | MPG city / hwy / combined |
|---|---|---|---|
| 2.0L 4-cyl turbo | 7-speed dual-clutch | FWD | 27 / 37 / 31 |
| 2.0L 4-cyl turbo | 7-speed dual-clutch | AWD | 24 / 34 / 27 |
| 2.0L 4-cyl turbo | 6-speed manual | AWD | 24 / 33 / 27 |
EPA ratings. Class: Compact car.
Frequently asked questions
Is the 2018 Audi A4 a good car?
Based on 45 owner complaints filed with NHTSA, the 2018 A4 rates better than average: 56% fewer complaints than a typical year of the A4 at the same age. Complaint counts don't account for sales volume or individual maintenance, so have any used car inspected before buying.
What is the most common problem with the 2018 Audi A4?
The electrical system — 17 complaints, 38% of all complaints for this model year, most often about starter assembly. Next are the body & structure (6) and engine & cooling (6).
How many recalls does the 2018 Audi A4 have?
There is 1 recall for the 2018 Audi A4, the most recent from November 10, 2021 (front passenger). Recall repairs are free at any authorized dealer — check whether yours has been done with the VIN recall check.
What are the best and worst years of the Audi A4?
The best years by complaints, compared at the same age, are 2011, 2016 and 2012. Years to avoid or approach with caution: 2020, 2008, 1998, 2006 and 1999. See the full Audi A4 years comparison.
At what mileage do 2018 Audi A4 problems happen?
The median mileage reported in complaints is about 14,000 miles; 75% of problems with a recorded mileage started before 50,000 miles.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.