Acura TL, TSX & MDX ABS / VSA Module Repair
The ABS-VSA modulator on the 2004–2014 Acura TL, TSX, MDX, RDX, and RL is one of the most common module failures we see. Here's how to confirm it's the module, what the codes mean, and the right way to fix it — without a $2,000 dealer unit.
Published June 29, 2026 · By TMW Repairs
Symptoms you'll see
- • ABS, VSA, and brake warning lights on at the same time
- • "Check VSA System" or VSA activation light on
- • Hill-start assist and traction control disabled
- • Cruise control kicks out or won't engage
- • Speedometer drops to zero intermittently
- • Scan tool can't communicate with the VSA module at all
Fault codes we see most
- 84-01 — VSA modulator-control unit internal failure
- 85-01 — VSA modulator-control unit power supply
- 66-11 — VSA solenoid valve malfunction
- U0121 — lost communication with ABS control module
84-01 and 85-01 are dead giveaways for internal control-unit failure. Wheel-speed sensors, brake switch, and steering-angle calibration will never clear these codes.
Vehicles affected
- • 2004–2008 Acura TL and TL Type-S
- • 2009–2014 Acura TL
- • 2004–2014 Acura TSX
- • 2007–2013 Acura MDX
- • 2007–2012 Acura RDX
- • 2005–2012 Acura RL
- • 2010–2013 Acura ZDX
Why it fails
The control unit bolts directly to the hydraulic pump in the engine bay. Years of heat cycling and vibration crack solder joints under the valve-driver chips, and the main ASIC eventually shorts internally. From the driver's seat it looks like every safety system on the car gave up at once — even though the brakes themselves are fine.
An Acura replacement modulator is $1,600–$2,200, requires bleeding, re-coding, and a VSA neutral-position memorization with HDS. None of that is needed if the original unit is repaired.
How TMW Repairs fixes it
- You unbolt just the control unit (4 Torx screws) and ship it with our prepaid FedEx label — the hydraulic block stays on the car, so no brake bleeding.
- We bench-test, confirm the failure mode, and replace the failed driver ICs and solder joints at component level.
- Every valve channel and CAN line is tested under simulated load before it ships back.
- You bolt it back on. No coding, no programming, no dealer trip — the lights are out before you leave the driveway.
Cost & turnaround
- • 2–3 business day turnaround once received
- • 1-year warranty on the repair
- • No coding, no programming, no bleeding
- • Roughly 80% cheaper than a new Acura modulator
Ready to send your Acura modulator in?
Start a repair online and we'll email you a prepaid FedEx label within minutes.
Questions buyers ask before sending it in
Which Acuras have this failure?
Most commonly 2004–2014 TL, 2004–2014 TSX, 2007–2013 MDX, 2007–2018 RDX, 2005–2012 RL, and the ZDX. Same Nidec/Continental modulator family as Honda Accord, Civic, and Pilot.
Do I have to replace the whole assembly?
No. Acura's replacement is $1,800–$2,400 plus coding. Component-level repair of the existing control unit reuses your original hydraulic block and stays VIN-paired.
Will brake bleeding be required after?
No. The hydraulic block never leaves the car — only the electronic control unit is shipped in.
Does the repaired unit need to be coded?
No. Your original control unit is returned with all factory calibration intact. Reinstall and drive.
How long does it take?
24–48 hour bench time plus return shipping. 1-year warranty on every repair.