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Acura · Known Issues

1991 Acura NSX Problems: 3 Known Issues

1991 model year · NHTSA recalls, manufacturer TSBs, and owner forum reports · Updated August 2026

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Issue summary

According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 1991 Acura NSX has 3 documented known issues, with 2 rated critical. The most serious are Snap-ring transmission failure on 1991-1992 NSX (serial range J4A4-1003542 to J4A4-1005978) ($2,500-$7,500 repair) and ALB/ABS modulator pump times out and pressure sensor fails on NA1 NSX (1991-1999) ($105-$2,600 repair). Across all issues with published estimates, repair costs range from $105 to $7,500. DIY maintenance guides at au7o.io.

In This Article

  • NSX Transmission1
  • NSX Brakes1
  • NSX HVAC1
  • FAQ
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In This Article

  • Transmission1
  • Brakes1
  • HVAC1
  • FAQ

All 3 Known Issues

Filter:
ALL YEARS199919981997199619951994199319921991

When Issues Typically Appear

Snap-ring transmission failure on 1991-1992 NSX (serial range J4A4-1003542 to J4A4-1005978)
30K-80K
ALB/ABS modulator pump times out and pressure sensor fails on NA1 NSX (1991-1999)
50K-150K
Climate control unit display pixel fade and dead buttons (1991-1999 NA1)
60K-150K
038K75K113K150K mi

On the 1991-1992 Acura NSX 3.0L V6 C30A, a manufacturing defect in early NSX 5-speed manual transmissions cut the countershaft snap-ring groove inside the case slightly too wide. Under load the snap ring twists repeatedly until it shatters, releasing metal fragments into the gear set. The failure is limited to a specific production run of transmissions numbered J4A4-1003542 through J4A4-1005978, installed in some — but not all — 1991 and 1992 model year NSXs. VIN does not predict membership in the range because transmissions were not installed in VIN-sequential order; the transmission serial number must be checked directly on the case.

Common Symptoms

  • Shifter moves fore and aft in 1st or 2nd gear during acceleration or deceleration
  • Loud crunch or mechanical grinding from transmission when snap ring fragments break loose
  • Metal particles visible in transmission fluid on drain
  • Difficulty engaging or popping out of 1st or 2nd gear
  • Transmission may eventually lock up entirely

How to Fix

Two paths: (1) Acura dealer transmission replacement runs about $7,000-7,500 in parts and labor — this swaps the entire assembly. (2) An NSX specialist (ScienceofSpeed, NSX Modified, etc.) can rebuild the existing transmission and replace the upper case half for around $2,500-4,675 depending on shop and gear set choice, saving $3,000-4,500 vs dealer. Preventive repair before failure (replacing the upper case while gears are still intact) is about 10 hours labor + $700 parts. If the snap ring has already shattered, debris in the gear oil mandates a full teardown — do not just refill and drive. Honda's original goodwill program tapered off sharply in 1999, so post-2000 repairs are owner-paid.

Owner tips & cautions

  • TipBefore you buy a 1991-1992 NSX, check the transmission serial number stamped on the case (J4A4 prefix). If it falls in the range J4A4-1003542 to J4A4-1005978, factor a $2,500-4,500 preventive rebuild into your purchase price — and walk if the seller can't provide it.
  • TipIf you already own an at-risk NSX and the snap ring hasn't failed yet, preventive replacement of the upper case half is dramatically cheaper than waiting for a full transmission destruction.
  • WarningHonda's original goodwill repair program is effectively closed (tapered off by 1999). Do not assume Acura will cover this in 2026.
Typical repair cost:$2,500 - $7,500

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On the 1991-1999 Acura NSX, the first-generation NSX uses an Anti-Lock Brake (ALB) hydraulic modulator with a high-pressure pump, accumulator, and pressure sensor. The pump is designed to charge the accumulator and then stop within 120 seconds. When internal O-rings dry and the pump can no longer build pressure — or when the pressure sensor itself fails — the pump runs continuously for the full 120 seconds before timing out, the ABS warning light comes on, and the system disables. Once the system disables, the car still stops on its base brakes but loses ABS function entirely. Acura's North American service policy mandates replacing the modulator, pump, and accumulator as whole assemblies (about $2,100 in parts alone, $2,600 total dealer cost) — but the failure is almost always either a $100 O-ring set or a pressure sensor, both serviceable internally.

Common Symptoms

  • ABS / ALB warning light comes on and stays on
  • Pump runs continuously for about 120 seconds before timing out
  • Loss of ABS function; base brakes still work but no anti-lock
  • Audible pump motor cycling when ignition is on
  • Blown ALB fuse on repeated key cycles

How to Fix

Three repair paths, from cheap to expensive. (1) DIY O-ring rebuild with the SOS or egmCarTech kit ($105-200), which replaces the brake-fluid-resistant O-rings inside the modulator; the kit includes a bleeder T-wrench and 28-piece O-ring set. (2) Professional rebuild by a specialist (AutoECU, ScienceofSpeed, etc.) for around $795 — they pull the unit, replace O-rings and the pump motor brushes if worn. (3) Dealer full-assembly replacement at $2,100-2,600. There is also a documented upgrade path to swap the 1991-1999 NA1 modulator for the 2000-2005 NA2 unit using the SOS conversion kit, which simplifies the system and improves long-term reliability. Before any repair, check that the failure isn't simply rodent damage to the pump motor wires under the car — a blown ALB fuse from chewed wires presents the same way and costs $10 to fix.

Owner tips & cautions

  • TipBefore assuming a $795-2600 repair, check for rodent damage on the pump motor wires under the car. Mice chewing the harness is a known NSX cause of ALB-fuse blowing that mimics modulator failure.
  • TipThere is an SOS NA2 conversion kit that swaps the 1991-1999 NA1 modulator for the simpler 2000-2005 NA2 unit. Documented on nsxfaq.com/upgrade-to-2000-2005-abs-using-sos-kit/.
  • WarningSome independent shops will sell you a full dealer-assembly replacement when an O-ring rebuild would have fixed it. Get a second opinion from an NSX specialist before approving a $2,000+ ABS bill.
Typical repair cost:$105 - $2,600

Research This Issue

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Manually Verified
High ConfidenceVerifiedReviewed May 2026

On the 1991-1999 Acura NSX, the NSX climate control unit (CCU) sits in the center console and uses an LCD display plus push-buttons to set temperature and fan. Over time the LCD pixels fade — typically starting at the top of the display and progressing down — until the temperature setting is unreadable. Separately or simultaneously, individual buttons stop responding because the conductive carbon pads on the rubber button backs wear off, and the circuit board's electrolytic capacitors dry out and leak. Acura's only remedy is full CCU replacement, which is typically out of stock or back-order from Honda parts and was originally priced over $1,000. Several NSX specialists rebuild the existing CCU for $150-300 by replacing the LCD, button pads, and capacitors — the unit then works like new and the original equipment is preserved.

Common Symptoms

  • Top rows of the LCD display fade or go blank
  • Temperature setting unreadable in daylight
  • Individual buttons (fan up/down, mode, defrost) stop responding
  • Display goes completely dark intermittently
  • Display works after cool weather but fades when cabin warms up

How to Fix

Mail-in CCU repair from an NSX specialist is the standard fix. ScienceofSpeed, AutoTechRescue, SpeedoFix, NSXe-repair, and ModuleRepairPro all offer rebuild service for around $150-300 with 1-3 day turnaround. Removal is a 20-30 minute job at home — pop the armrest, shift knob, ashtray, and center console trim, then four screws hold the CCU. Reinstallation requires no programming or coding. Avoid full Acura CCU replacement: even when available, the part is over $1,000 and the rebuilt original works identically. Common rebuild scope: LCD module, all rubber button pads, electrolytic capacitors C1/C2/C3 on the main board, and reflow on heat-stressed solder joints.

Owner tips & cautions

  • TipDon't pay Acura $1,000+ for a replacement CCU when the original can be rebuilt for under $300. The rebuilt unit works identically and requires no coding to reinstall.
  • TipRemoval is DIY-friendly (20-30 min). Pop the armrest, shift knob, ashtray, console trim, then 4 screws hold the CCU. Two connectors disconnect by hand.
  • WarningMultiple specialists offer this service — AutoTechRescue, SpeedoFix, NSXe-repair, ModuleRepairPro. Get a quote from 2+ before shipping, prices vary $50-100.
Typical repair cost:$150 - $1,000

Research This Issue

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Frequently Asked Questions

What are the most common Acura NSX problems?

According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 1991 Acura NSX has 3 documented issues. The most frequently reported are: Snap-ring transmission failure on 1991-1992 NSX (serial range J4A4-1003542 to J4A4-1005978), ALB/ABS modulator pump times out and pressure sensor fails on NA1 NSX (1991-1999), Climate control unit display pixel fade and dead buttons (1991-1999 NA1). Of these, 2 are rated critical and should be addressed promptly.

Is the Acura NSX reliable?

The 1991 Acura NSX has 3 known issues compiled from NHTSA recalls, manufacturer TSBs, and owner forum reports. 2 issues are rated critical: Snap-ring transmission failure on 1991-1992 NSX (serial range J4A4-1003542 to J4A4-1005978) and ALB/ABS modulator pump times out and pressure sensor fails on NA1 NSX (1991-1999). Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.

How much does it cost to fix common Acura NSX problems?

Repair costs for known Acura NSX issues range from $105 to $7,500, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, Snap-ring transmission failure on 1991-1992 NSX (serial range J4A4-1003542 to J4A4-1005978), typically costs $2,500-$7,500 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.

What is the 1991-1992 Acura NSX Snap-ring transmission failure on 1991-1992 NSX (serial range J4A4-1003542 to J4A4-1005978)?

A manufacturing defect in early NSX 5-speed manual transmissions cut the countershaft snap-ring groove inside the case slightly too wide. Under load the snap ring twists repeatedly until it shatters, releasing metal fragments into the gear set. The failure is limited to a specifi… Repairs typically run $2,500-$7,500. Severity: high.

What is the 1991-1999 Acura NSX ALB/ABS modulator pump times out and pressure sensor fails on NA1 NSX (1991-1999)?

Content on this page was compiled with AI assistance using NHTSA complaints, TSBs, owner reports, and public automotive data. While we strive for accuracy, this information may contain errors. Always verify repair procedures and specifications with your vehicle's service manual or a qualified mechanic.

Data compiled from NHTSA recalls, manufacturer TSBs, automotive forums, and AI-assisted research. No aggregated owner-report counts available for this vehicle yet.

The first-generation NSX uses an Anti-Lock Brake (ALB) hydraulic modulator with a high-pressure pump, accumulator, and pressure sensor. The pump is designed to charge the accumulator and then stop within 120 seconds. When internal O-rings dry and the pump can no longer build pres… Repairs typically run $105-$2,600. Severity: high.

What is the 1991-1999 Acura NSX Climate control unit display pixel fade and dead buttons (1991-1999 NA1)?

The NSX climate control unit (CCU) sits in the center console and uses an LCD display plus push-buttons to set temperature and fan. Over time the LCD pixels fade — typically starting at the top of the display and progressing down — until the temperature setting is unreadable. Sep… Repairs typically run $150-$1,000. Severity: medium.