Question 1

What is the most cost-effective way to replace a 2017 Acura RLX smart key?

Accepted Answer

Start by matching exactly what you have. The 2017 RLX uses a five-button smart key, and the dealer part number on yours will tell you which memory-seat position it was assigned to. There are separate part numbers for the first and second driver memory positions, so if you're replacing a lost key, knowing which one you had matters for keeping the seat and mirror memory tied correctly.

A genuine OEM replacement is the safest bet for reliability. Aftermarket fobs are available at lower cost, but the transponder chip inside has to match what the vehicle's immobilizer expects, and not every aftermarket unit gets that right. A fob that passes the button test can still fail to start the car if the transponder side is off.

The dealer process is: order by VIN, prove ownership, come back with the car for a programming appointment, which sometimes means two separate trips if the part isn't on the shelf. I'm mobile and come to you in East Ventura, cut the emergency insert on site, and register the new fob in one visit, for way less than the dealer route.

Question 2

How different is all-keys-lost on a 2017 RLX compared to just adding a spare?

Accepted Answer

Significantly different. Adding a spare when you still have one working key is the simpler job. The car recognizes an existing registered fob, and I'm adding a new key ID alongside it.

All-keys-lost is a different animal. The vehicle's keyless access system has to go through a full reset, which requires erasing the existing key memory entirely before any new key can be registered. On the 2017 RLX, that reset process involves pulling authorization data tied to the vehicle's security system, and that data comes from the manufacturer's dealer network. You can't do this with a generic OBD programmer off a shelf. The missing fobs get wiped in the process, so they can't start the car afterward.

Dealers treat all-keys-lost as a security-level job with more time and documentation involved. Plan on the car being unavailable for a meaningful stretch, not a quick drop-in.

Question 3

Do aftermarket smart keys actually work on a 2017 Acura RLX, or is OEM the only option?

Accepted Answer

Aftermarket fobs exist and some do work, but there are two layers to "works" on this car. The buttons need to function, and the transponder inside needs to be accepted by the immobilizer. If the transponder specification doesn't match what the vehicle expects, the car will crank and immediately stall, or it won't authorize the start at all. The buttons working fine tells you nothing about whether the transponder side will pass.

Used OEM fobs are their own separate risk. Many of them are already registered to another vehicle. A fob that's been previously paired can fail enrollment because it isn't in a virgin state. You'd be paying for a real fob that the car won't accept.

When a key-not-detected warning stays on the dash after a swap, that's usually the signal that something on the car side needs diagnosis, not just a different fob purchase.

Question 4

The door handle touch unlock stopped working on my 2017 RLX. Is that the fob or the car?

Accepted Answer

If the push-button start still sees the fob and the other door handles still work, the fob is almost certainly fine. Touch unlock on the RLX runs through sensors built into each door handle, and those sensors are car-side hardware, not fob-side. A single handle acting up while others work normally points to that door's sensor or its wiring, not the key.

Clean the handle area first. Dirt and moisture can interfere with the capacitive sensor. If it stays isolated to one door after that, it's a door-side diagnosis.

Question 5

My 2017 RLX key fob battery is new but the range is still terrible. What else could cause this?

Accepted Answer

A few things come up on the RLX specifically. First, pull the fob off the key ring entirely and test it away from your phone. Metal contact and proximity to devices in the 900 MHz range genuinely affect this fob's performance, and the owner's manual calls this out directly.

Second, check that the CR2032 is seated flat and the battery contacts haven't developed any corrosion or slight bend from a previous pry-open. A crooked battery can read fine on a tester but make intermittent contact inside the fob during normal use.

If range is still short after both of those, the fob's internal antenna or board may be damaged. That's when it makes sense to swap into a new housing or look at a replacement fob altogether rather than chasing a battery issue that isn't there.

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