Service Bulletin - During engine start in cold conditions, a miscalculation in the PCM causes the air-fuel ratio to exceed DTC rich criteria.
full bulletin at NHTSA ↗2021 Acura TLX powertrain problems
moderate Owners of the 2021 Acura TLX have filed 23 NHTSA complaints about the powertrain at roughly $2,500 to repair (U.S. federal records, as of July 2026). Source: NHTSA Office of Defects Investigation. See powertrain across all vehicles →
Complaints
23
Recalls
0
Avg fix
$2,500
| Model year | powertrain complaints |
|---|---|
| 2017 TLX | 18 |
| 2018 TLX | 10 |
| 2019 TLX | 10 |
| 2020 TLX | 7 |
| 2021 TLX (this page) | 23 |
| 2022 TLX | 9 |
What stands out
Powertrain accounts for 36% of every owner complaint on file for this vehicle — the dominant problem area across 6 categories tracked.
Among the 8 model years of Acura TLX in our records for powertrain problems, this one ranks #2 by owner-complaint volume.
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering powertrain on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
Service Bulletin - The MIL comes on with DTC P061B (PCM Internal Malfunction) is stored.
full bulletin at NHTSA ↗Service Bulletin - The MIL comes on with DTC P061B (PCM Internal Malfunction) is stored.
full bulletin at NHTSA ↗Service Bulletin - The MIL comes on with DTC P0236 (Turbocharger Boost Sensor Circuit Range/Performance Problem) stored.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
Owners of 2021 Acura TLX vehicles—particularly SH-AWD and A-Spec models—describe sudden transfer case failures occurring without warning or dashboard alerts. The failure is typically marked by a loud pop or bang from underneath the vehicle during normal acceleration or low-speed driving. After the noise, the rear wheels lose power entirely; the car defaults to front-wheel drive and feels noticeably front-heavy. Some owners report spline stripping between the transmission and transfer case as the root cause. Mileage ranges from as low as 16,500 miles to 71,000 miles.
Transmission issues also appear frequently. Owners report slipping, refusal to upshift (engine revs but car stays in first gear), and hard shifts into reverse. Brown sludge or fluid leaks appear around the transmission and differential seals. One owner with recent fluid service (July 2024) still experienced failure at 84,300 miles.
Rear differential fluid leaks at the driveshaft connection are cited at very low mileage. Owners note similar recalls issued for Honda CR-V and Accord.
Early complaints describe intermittent warning lights for Auto Idle Stop and Automatic Lighting Control systems; in one case, a cascade of system alerts (VSS, braking, steering, emission, AWD, brake system warnings) appeared simultaneously. Minor issues include door lock failure and sporadic Bluetooth connectivity in early ownership.
Same Acura TLX powertrain reports on nearby years: 2018
Failure modes owners describe
Transfer Case / Power Transfer Unit (PTU) Failure
The transfer case (PTU) in the SH-AWD system fails suddenly during normal driving, often accompanied by a loud pop or bang noise. Owners report loss of rear-wheel power, with the vehicle reverting to front-wheel drive operation. Spline stripping between the transmission and transfer case is cited in multiple complaints. No warning lights or system alerts precede the failure.
When: Varies widely; complaints cite early mileage (under 20k) to higher mileage (71k+). One narrative reports failure 'early 2025' on an unspecified model year.
Symptoms owners cite: Loud pop or bang from underneath the vehicle during normal acceleration; Loss of power to rear wheels; vehicle operates as front-wheel drive only; Noticeably front-heavy weight transfer and torque delivery during acceleration; No warning lights or dashboard alerts before failure; No grinding sounds, fluid leaks, or vibration reported at time of failure
Repairs/costs cited: Complete replacement of transfer case (PTU) required; often paired with transmission replacement. Dealers cite spline stripping as the root cause. Some owners report out-of-pocket costs due to being outside powertrain warranty window; others covered under manufacturer's 6-year/60k powertrain warranty.
Recalls/TSBs owners mention: Acura dealerships confirm diagnosis and approve replacement under powertrain warranty (6 year/60k) where applicable. No recalls issued at time of complaints; owners request formal investigation and recall consideration.
Transmission Failure / Internal Degradation
Transmission fails to shift or upshift properly, often after prolonged operation. Internal wear and slipping reported. Fluid leaks from transmission seals, particularly at the transmission-to-differential interface. Brown sludge leakage observed. Failures occur both within and outside warranty coverage.
When: Reported at 84,300 miles (complaint #4, confirmed in update #8); other mileages not specified. One vehicle had recent fluid service (July 2024) prior to failure.
Symptoms owners cite: Engine revs but transmission fails to upshift; vehicle stuck in first gear; Hard and abrupt engagement when shifting into reverse; Transmission slipping; Fluid leaking from transmission seal at transmission-to-differential interface; Brown sludge visible in leakage; Burning oil or rubber smell
Repairs/costs cited: Complete transmission replacement required. One owner reports recent fluid service (drain and refill with inspection) did not prevent failure. Repairs performed at Acura dealerships.
Recalls/TSBs owners mention: Dealerships diagnose as internal transmission failure and recommend replacement. Some coverage under powertrain warranty (6 year/60k); warranty status disputed in one complaint due to timing of service visit.
Rear Differential Fluid Leak
Fluid leaks from the rear differential where the driveshaft connects. Complaint cites potential recall on Honda CR-V and Accord for the same issue, suggesting a platform-wide concern.
When: Reported at 16,531 miles (complaint #9); other instances mentioned in complaints #5 and #10 but without specific mileage.
Symptoms owners cite: Fluid leaking from rear differential at driveshaft connection; Brown sludge visible in transmission and differential area
Repairs/costs cited: Transmission and transfer case replacement required when combined with other failures. Leak alone not separately repaired in narratives provided.
Recalls/TSBs owners mention: No manufacturer response specifically addressing differential leaks. Owner notes Honda is releasing recall for CR-V and Accord; Acura TLX owners request inclusion in recall.
Auto Idle Stop and Automatic Lighting Control Warning Light Intermittency
Warning lights for Auto Idle Stop and Automatic Lighting Control systems activate intermittently while driving. Lights come on and off without clear trigger, sometimes with multiple system warnings appearing simultaneously. Dealership unable to replicate or diagnose root cause when lights are not actively illuminated.
When: Early ownership (3,275 to 3,910 miles at first dealership visits); warning lights continue for weeks.
Symptoms owners cite: Auto Idle Stop warning light comes on intermittently while driving; Automatic Lighting Control warning light comes on intermittently while driving; Multiple warning lights (VSS, Hill Start Assist, Adaptive Cruise Control, Collision Mitigation Braking System, Road Departure Mitigation System, Emission System, AWD System, Brake System, Electric Parking Brake, Electric Power Steering) reported in one severe instance
Repairs/costs cited: Dealerships unable to diagnose when lights not currently illuminated. One dealership mentions something may have occurred during vehicle wrap installation but repair details not provided.
Recalls/TSBs owners mention: No specific recall or TSB cited. Dealerships unable to provide diagnosis or fix.
Door Lock Failure
Vehicle door would not unlock even with physical key insertion. Occurred early in ownership and required roadside assistance. One dealership speculated the issue occurred during post-delivery wrap installation.
When: September 6, 2021 (complaint #1) at 3,275 miles
Symptoms owners cite: Vehicle will not unlock with key; Owner stranded in parking lot
Repairs/costs cited: Lock eventually released on its own before roadside assistance arrived. Dealership speculated issue related to vehicle wrap installation.
Bluetooth / Infotainment System Intermittency
Bluetooth HandsFree Link system operates sporadically. Phone calls ring through even after they have been answered, indicating handoff issues between phone and vehicle system.
When: Early ownership (3,275 miles at first report)
Symptoms owners cite: Bluetooth connection intermittent / sporadic; Phone rings even after call has been answered
Synthesized from 23 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 5 most recent
The vehicle VIN - [XXX] The vehicle, 2021 Acura TLX, was purchased on June 8, 2021, from the showroom floor of Metro Acura Dealership. The vehicle was sold as being compatible with iPhone, Bluetooth HandsFree Link, and Apple CarPlay. Not to mention the innovative technology, Automatic Lighting Control, and Auto-Idle Stop System. The vehicle was purchased with a full 4 year/50,000-mile…
Noticed my 2021 Acura TLX A-SPEC SH-AWD has fluid leaking from the rear differential where the driveshaft connects. The vehicle has 16,531 miles on the odometer. Honda is releasing a recall for leaking rear differential on the Honda CRV as well Accords. Honda may want to include the Acura TLX's as well in the recall as they are reporting the drivesshaft may cause serious damage at high speeds if…
I took this vehicle to get serviced in the summer of 2025. I recently joined an Acura Type S (2021+) group on Facebook and learned that the issue is quite prevalent. I had to have the transmission and transfer case replaced due to transmission issues and traction issues
On July 7th 2026 I was driving home, came to a stop light at normal speed, when the light turned green I took off at normal speed and I heard a huge cluck / bang from underneath the car and it bogged and didn’t want to move. I then stepped on the gas because of the Car behind me getting to close and my traction control light started to flash and the car started to shake and feel very…
Transmission splines went out and transfer case has also failed which is only sending power to front wheels
Had powertrain trouble with your 2021 Acura TLX?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the powertrain problem on the 2021 Acura TLX?
It's a documented issue but not catastrophic. 23 complaints have been filed. Repairs average $2,500 and most owners catch it before it causes a breakdown.
At what mileage does the powertrain typically fail?
Based on the 23 complaints filed, powertrain issues most often appear around 93,039 miles. Some report problems earlier; some make it well past 150,000 with no symptoms. Maintenance habits matter — vehicles that received timely fluid services and were not regularly overworked tend to last longer.
What does it cost to fix?
Independent shops typically charge around $2,500 for powertrain repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to powertrain?
No active recalls currently cover powertrain issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2021/Acura/TLX.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.