What are the most common problems on the 2018 Audi A4?

Q: What are the most common problems on the 2018 Audi A4?

NHTSA has 42 owner complaint(s) on record for the 2018 Audi A4. Electrical System is the most-reported problem area on the 2018 Audi A4, cited in 16 of 42 filed complaints (38%).

Problems › Audi › 2018 A4

2018 Audi A4 Problems & Owner Complaints

42 NHTSA owner complaints

1 crash

Age-normalised, this year draws ~4.7 complaints per year on the road — ranking 5 of 11 Audi A4 years we track (1 = most complaints per year).

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What owners report

Electrical System is the most-reported problem area on the 2018 Audi A4, cited in 16 of 42 filed complaints (38%).

Fuel/Propulsion System is next (6 complaints, 14%), followed by Structure (6), Engine (5), Power Train (5).

Across all complaints, 1 report a crash.

The most safety-critical cluster is Steering: 1 crash report(s).

Complaints by vehicle system

Owner complaints filed with the U.S. NHTSA for the 2018 Audi A4, grouped by the vehicle system each cites. A single complaint can name more than one system, so the group totals can add up to more than 42.

Unknown Or Other 18

“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 r…”
NHTSA complaint #11747862, 2026

“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 infor…”
NHTSA complaint #11747863, 2026

“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, bu…”
NHTSA complaint #11747808, 2025

Electrical System 16

“This problem is extremely sporadic, and often remedies itself after car shut down, and sometimes require that the car sit for a period of time. I estimate the following issue happens ~1 time a month, or estimated 5% of the time. Weather (temperature specifically) does not appear to impact occurance. When reversing, at times the back up camera does not function properly. During these times, the parking sensors appear to work, but it's unclear if the emergency reverse automatic braking system is working. The backup camera issues present themselves in several different ways and are described…”
NHTSA complaint #11709539, 2025

Fuel/Propulsion System 6

“The fuel filler door/gas door intermittently fails to open, preventing normal access to the fuel filler area. This appears to involve the fuel door latch, release mechanism, lock actuator, body component, electrical control, or related wiring/module issue. This is being reported as a safety concern because inability to open the fuel door can prevent refueling when fuel is low. If the vehicle cannot be refueled, it can create a stranding risk or loss-of-propulsion risk, including in traffic, at night, on a highway, or in an unsafe location. The issue also creates driver distraction and uncerta…”
NHTSA complaint #11747847, 2024

“The engine oil level has been gradually dropping and has required monitoring and/or adding oil between normal service intervals. The exact source is unknown. It may involve abnormal oil consumption, an external oil leak, internal engine oil consumption, PCV/oil separator issue, turbo-related oil consumption, gasket/seal issue, or oil loss that is not leaving an obvious visible puddle. This is being reported as a safety concern because low engine oil or abnormal oil loss can lead to low oil pressure, warning messages, engine overheating or damage, smoke, oil contacting hot engine/exhaust compo…”
NHTSA complaint #11747848, 2024

Structure 6

“Visible wiring has become exposed in the windshield/A-pillar area. There is no airbag/SRS warning light at this time, and I am not able to determine from visual inspection whether the exposed wiring is related to the restraint system. However, this is a safety-sensitive area because it can contain or route electrical wiring near trim, sensors, and safety-system areas. Exposed or unsecured wiring in this area may create a risk of electrical short, damaged wiring, impaired signal integrity, loose trim, moisture intrusion, or safety-system malfunction. The concern was reported as part of broader…”
NHTSA complaint #11747810, 2024

“The sunroof has a recurring mechanical/electrical malfunction. During operation, the sunroof binds and makes a loud popping or cracking noise, and the rubber seal became torn or damaged. This suggests a possible track, guide, cable, motor, regulator, frame, seal, or alignment failure. This is being reported as a safety concern because a binding or popping sunroof can distract the driver, allow water intrusion into electrical areas, worsen into glass/track/frame failure, or create a risk of loose roof components while the vehicle is in use. The issue was reported to Audi service and was not fu…”
NHTSA complaint #11747811, 2024

Engine 5

“Water Pump prematurely failed. Upon self inspection, I noticed the coolant reservoir was below the minimum requirements. I asked the dealer to inspect, and they determined the cause was a faulty water pump. At around 50,000 miles, this water pump should not have failed under normal use. I am fortunate I self inspected, as continued use may cause premature engine failure due to overheating. Overheating would cause spontaneous vehicle operation failure during normal driving conditions, stalling the vehicle on a road or highway, putting myself and others at risk for impact.”
NHTSA complaint #11489365, 2022

Power Train 5

“The all-wheel-drive clutch in the vehicle had to be replaced. The symptoms were heavy vibrations or thumping when starting to drive forward from a stop with the wheels turned in either direction. A dealership - New Country Audi of Greenwich - did the repair at a cost of $4,308.85 (including tax). This drivetrain failure occurred at less than 48,000 miles. The vehicle came with a 50,000 mile or 4 year warranty. Since it was in service for over 5 years, this defect was not covered under warranty. There is a Techical Service Bulletin on this issue, number 39 21 43 2059057/4 July 16, 2021. The…”
NHTSA complaint #11547846, 2023

“While driving there was an internal failure of the front differential which caused debris to fly out and the debris then punctured the transmission according to the diagnosis on an Audi dealership. The car jerked to a stop and would not move. If this happens at high speed it represents a sever safety risk to the occupants. The vehicle has been inspected by the manufacturer and insurance representatives as well as by a dealer. There were no warning lamps, messages or other symptoms and this happened with no warning.”
NHTSA complaint #11539793, 2023

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Air Bags 4

“Without cause a passenger airbag malfunction light has come up, dealership says this is not covered under recall or vehicle warranty.”
NHTSA complaint #11512210, 2023

“The vehicle is subject to a Passenger Occupant Detection System / PODS safety recall involving the front passenger seat occupant-detection system and passenger airbag status. The concern is that the system may incorrectly detect whether a passenger is seated and may switch off or affect the front passenger airbag when the seat is occupied. This is being reported because the recall remedy was not completed, was delayed, was not properly resolved, or the concern remains unresolved. A malfunctioning passenger occupant detection system can affect whether the passenger airbag deploys as intended i…”
NHTSA complaint #11747852, 2022

“I first received notice of this recall in 1/22. My Audi dealer has continuously stated that Audi does not send them enough kits to remedy this recall”
NHTSA complaint #11524991, 2022

Forward Collision Avoidance 4

“My screen turns on and off consistently not allowing me to use my backup camera. Causing a small collision while backing up when the camera turned off unexpectedly. Additionally when it’s off it will auto break when I’m not close enough to hitting and it’s loud and yanked me. This has been an issue for some time and I’m seeing a significant amount of my models have this issue and it’s not safe.”
NHTSA complaint #11702346, 2025

“I am reporting recurring safety-related defects on my 2018 Audi A4 involving Automatic Emergency Braking, Forward Collision Warning, Audi pre sense/front-collision functionality, and related electrical/driver-assistance reliability. The AEB/forward-collision system has shown two unsafe intermittent behaviors. At times it has failed to activate as expected when crash-mitigation assistance appeared reasonably available. At other times it has unexpectedly warned, jolted, or applied braking when there was no apparent vehicle, object, pedestrian, or hazard close to the car. Unexpected braking or f…”
NHTSA complaint #11741957, 2024

“The forward collision warning system (Audi PreSense) identified a shadow from an overpass as another car and alerted me to use the brakes. My car did figure out there was not another vehicle before performing an emergency brake. If the car had done an emergency brake I would have surly been rear ended on the highway. This is not the first time forward collision warning has activated due to a shadow on the road. I have not mentioned this to the dealer but have read of this happening to others that own Audi cars that use Audi PreSense. The Audi PreSense installed in my car utilizes the front fa…”
NHTSA complaint #11469403, 2022

Service Brakes 3

“An Audi dealer installed 245/40R18 93H tires on this 2018 Audi A4, while the vehicle placard/specification requires 245/40R18 97H. The lower load index reduces capacity from 1,609 lb per tire to 1,433 lb per tire, approximately 704 lb total across four tires. This creates a safety risk because load-rated tires affect vehicle stability, heat buildup, braking, steering/cornering, suspension loading, and tire failure/blowout risk. After discovering the mismatch, the concern was reported to the dealer and Audi, but the dealer stated the 93H tires were acceptable rather than providing a safety-bas…”
NHTSA complaint #11747798, 2023

“While driving the emergency parking brake engaged itself without warning or cause. This caused the vehicle to come to an abrupt stop. Luckily I was in a parking lot but if I had been in a high traffic area or intersection, it could’ve caused a collision. I had 2 passengers who witnessed this sudden bizarre event. There was nothing that could’ve caused this to happen. It scares me & now I’m worried this could happen again without warning. The sensor screen was beeping with a message to put my car in park before setting the brake. Made no sense why this happened.”
NHTSA complaint #11441169, 2021

“NEW FACTORY BRAKES MAKE VERY LOUD AUDIBLE SCREECHING SOUND WHEN COMING TO A STOP.THIS HAPPENS JUST BEFORE COMING TO A COMPLETE STOP AND SOMETIMES IN THE BEGINNING OF BREAKING. MECHANIC HAS WORKED ON THIS ISSUE SEVERAL TIMES AND REORDERED BRAKES FROM LOCAL AUDI DEALERSHIP AND IT IS STILL MAKING THE SOUND. DEALERSHIP SAID ITS 4TH GENERATION BRAKES AND ITS A PROBLEM WITH THE COATING.”
NHTSA complaint #11279066, 2019

Back Over Prevention 2

“The rear-view camera intermittently fails to engage when the vehicle is shifted into reverse. When the camera does display, the image sometimes shows horizontal glitch lines/artifacts. This affects backing visibility and parking safety and creates a risk of collision with pedestrians, objects, vehicles, or property. The concern was reported to Audi service along with other electrical/driver-assistance symptoms, suggesting a possible camera, wiring, module, signal-processing, or broader electrical fault. No crash, fire, injury, or fatality occurred. This complaint is being submitted because th…”
NHTSA complaint #11747799, 2024

Suspension 2

“Fortunately no catastrophic failure or accident occurred. At about 40,000k miles the rear spring mounts are significantly corroded and need replacing. This appears to be a galvanic reaction that occurs due to a design flaw which shortens the life of the critical mounts. I’m told one could fail imminently and the other is headed that way. Had this failed in use the damage would be significant and caused an accident. The service advisor said that Audi is aware of the short lifespan and has an improved version that will be used in the repair. I have a video of one of the mounts and will re…”
NHTSA complaint #11622923, 2024

Electronic Stability Control (Esc) 1

“I WENT TO PRESS THE BUTTON TO DISABLE START/STOP MODE. THE BUTTON TO DO THIS IS NEXT TO THE ELECTRONIC STABILITY CONTROL BUTTON. I ACCIDENTALLY PRESSED THE ESC BUTTON AND SHUT OF ELECTRONIC STABILITY. **THESE TWO BUTTONS SHOULD NOT BE NEXT TO EACH OTHER. ** THERE SHOULD BE A WAY TO DEFAULT TO DISABLED START/STOP MODE.”
NHTSA complaint #11343855, 2020

Engine And Engine Cooling 1

“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 awar…”
NHTSA complaint #11717605, 2026

Seats 1

Steering 1 1 crash

“I was rear-ended at a slow speed. I was stopped at the time. The driver who hit me was decelerating hard. Damaged to rear bumper. When I got back in the car, I realized that telescoping steering column had been pulled toward me. This would have been bad had I been shoved into the car in front of me and the airbags deployed too close to me. Luckily, this did not happen.”
NHTSA complaint #11567780, 2024 · crash

Visibility/Wiper 1

“The exterior side mirrors have intermittent electrical/memory malfunctions. When locking the vehicle, the side mirrors begin to fold, pause or glitch briefly, and then continue folding. Separately, when the vehicle is shifted into reverse, the right-side mirror tilts downward to assist with backing/parking, but when shifted back to drive or park, the mirror does not reliably return to its original saved position and requires manual readjustment. This is being reported as a safety concern because exterior mirror position affects rearward and side visibility, backing visibility, lane-change awa…”
NHTSA complaint #11747845, 2024

Wheels 1

How we read this (methodology)

How to read this: raw complaint totals are not a clean reliability score — a model year with more cars sold, or simply more years on the road, accumulates more complaints regardless of how good it is. So this page leans on two signals that are not distorted by sales volume: the share of complaints falling on each vehicle system (the breakdown above) and NHTSA's own crash / fire / injury / death flags. When we compare model years of the same model, we normalise by years on the road (complaints ÷ vehicle age) rather than comparing raw totals. Age-normalised, the 2018 Audi A4 draws about 4.7 complaints per year on the road, ranking 5 of 11 among the Audi A4 model years we have ingested (1 = most complaints per year on road).

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Data source: U.S. NHTSA (nhtsa.gov). SaveVIN surfaces public recall data and is not affiliated with or endorsed by NHTSA.