Rav4 Has stopped recognising the fobs

That’s odd as they have the same looking key...3 button Lexus/Toyota 🤔🤔

OP has already tried that Charlie :TU:

There are a few standards. In Europe it's the EMC directive (I think 2014/30/EU at the moment) that deals with emissions and susceptibility, although it only requires a manufacturer to prove due diligence with respect to EMC (Electro-magnetic compatibility). - it does not define test standards or levels.

The accepted way of showing due diligence is to test to a standard from other organisations such as CISPR or ETSI or others.

The testing is quite involved and the following is a vast over simplification but generally:

Domestic stuff will be tested to around - 3 V/m (Volts per meter is an E-M field strength measurement, you might also see Amps/m).

Industrial & maybe more critical medical - 10 V/m

Vehicles (components) generally 200 V/m - Although this varies. I've seen 600 V/m asked for. Vehicle manufacturers tend to define extra requirements. For cars, usually each component (e.g. an ECU) will go through some sort of separate pre-compliance test (at the 200V/m level) before the manufacturer will accept it onto the vehicle for the final "Homologation" test. Trucks tend to be more "modular", i.e. no one truck is often build to the same spec as another, so each component usually goes through the approval separately, rather than a single "all components" homologation test, like cars.

"Why do you ****ers charge so much for ECUs, when I can by other electronics so cheap?, whinge, whinge" - Yeah, right, see above for a start.

Rail - Dunno. Probably similar or higher field strengths than vehicles.

Aircraft - Higher still.

Some of the issues with the fobs is that a large percentage operate in a band that:

1. It's also occupied by legitimate, licenced, much high power users that were there before key fobs.
2. The "licence free" part of the band is a free for all. e.g. continuous transmitting devices competing with very low "duty-cycle" devices like fobs.

There are others. Why the fobs were put at those frequencies in the first is another story. I've wittered on too much already.

Department of trade and industry Ash. OFCOM have responsibility for checking radio interference now.

With a directional antenna like a short-ish (for easy of handling) Uda-Yagi (possibly tuned to around 70cms) and a spectrum analyser. Or possibly a scanner if the "interference" is narrow-band (which it probably is).

Sounds like a classic fob receiver blocking problem to me and I've investigated a few in the far dim & distant past. The source is probably long gone by now.