Land Rover and Jaguar Keyless Module Faults in Southlake: When a New Fob Will Not Fix It
Land Rover and Jaguar RFA keyless module and antenna faults in Southlake TX — why intermittent no-detect is a module problem, not a key problem. Call or text (972) 573-7978.
Land Rover and Jaguar Keyless Module Faults in Southlake: When a New Fob Will Not Fix It
There is a specific Land Rover and Jaguar complaint that costs owners more money than any other, and it is not a lost key. It is the car that detects your fob most of the time. People buy a second fob, then a third, and the intermittency never goes away — because the fault was never in the key. Southlake TX Locksmiths diagnoses keyless system faults across Southlake, Colleyville, Keller, Grapevine, Westlake and Trophy Club. Call or text (972) 573-7978.
Quick Answer
Keyless entry and start on Land Rover and Jaguar vehicles runs through a remote function and keyless module — commonly called the RFA — plus a set of antennas distributed around the vehicle. When that module or one of its antennas degrades, the symptom is intermittent key detection that looks exactly like a failing fob.
The test that separates them is free: if two known-good fobs both fail in the same way, the fault is on the vehicle side. Diagnosis runs $120 to $280 and is worth every dollar compared to buying fobs that change nothing.
Land Rover and Jaguar Module Work Pricing in Southlake
| Job | Typical range |
|---|---|
| Keyless system diagnosis | $120–$280 |
| Antenna fault isolation | $150–$350 |
| Keyless / RFA module programming (OBD-reachable) | $300–$700 |
| Module work requiring bench access | Quoted per job |
| Immobilizer diagnosis | $90–$220 |
| Key programming (when the key genuinely is the fault) | $400–$900 |
As of July 2026. Ranges only. Model, year and which component has failed set the figure. Diagnosis comes first — we do not quote a module replacement before proving one is needed.
How the keyless system actually works
Understanding the architecture makes the diagnosis obvious.
Your fob does not talk directly to the engine. It talks to a receiver. The keyless module manages a set of low-frequency antennas placed around the vehicle — in the doors, in the cabin, near the boot — that create detection zones. When you touch a door handle, the module energizes the relevant antenna, the fob answers, and the module authorizes the door. When you press start, an interior antenna confirms the fob is genuinely inside the cabin before authorizing.
Everything about that chain is directional and zone-based, which is exactly why its failures are positional and intermittent. One dead antenna does not kill the system — it kills one zone. That is why the driver door works and the passenger door does not, or why the car sees the fob in the cupholder but not in your pocket.
A key, by contrast, either works or it does not. Keys fail abruptly and completely. Antennas and modules fade.
The five signatures of a vehicle-side fault
Two different fobs behave identically. The single most decisive test, and it is free. Two independent keys with independent batteries and independent electronics do not fail simultaneously in the same pattern. If both do the same thing, stop suspecting the keys.
Position determines success. Works from the driver door but not the boot. Detected on the console but not in a jacket. That is zone mapping, and zones belong to antennas.
It degraded gradually. A key that goes through the wash fails on Tuesday and worked fine on Monday. Antenna and module degradation is a story that starts with "it has been getting worse for a few months."
It correlates with weather or vehicle state. Worse in the cold, worse when damp, worse after the car has been sitting. Electronic connection and moisture-ingress faults behave this way; keys generally do not.
Fresh batteries changed nothing. If a new coin cell in both fobs made no difference, the fob's transmit side is probably fine — the receive side of the conversation is where to look. Rule the simple things out first, though: our key fob not working guide covers the free checks worth doing before any of this.
When it genuinely is the key
To be fair to fobs, they do fail, and there are signatures for that too.
Only one fob is affected. The other works everywhere, every time. That is the clearest possible key-side result.
It followed an event. A wash cycle, a swimming pool, a hard drop onto concrete. Water in particular is decisive — see our key fob water damage guide for what is recoverable and what is not.
Physical damage is visible. A cracked case, a corroded battery contact, buttons that have collapsed.
The car reports nothing at all. Complete silence rather than intermittent recognition. Total absence usually means the fob is not transmitting.
If the fob really is the problem, the Land Rover spare key guide covers pricing and process for replacement.
Module programming and what it involves
When a keyless module genuinely has failed and needs replacement, the module is not a plug-and-play part. It has to be configured to your specific vehicle — matched to the VIN, to the existing key credentials and to the rest of the security architecture — or the car simply will not accept it.
Two paths exist. On many vehicles the module can be programmed through the diagnostic port, and that is a mobile job at your address. On others the module has to be removed and worked directly, which is a different appointment entirely. Our bench versus OBD programming guide explains what changes.
A complication specific to newer vehicles: a security gateway sits between the diagnostic port and the modules that matter, and getting through it legitimately is an additional step. The security gateway module guide covers it, and it is something we identify from your VIN in advance rather than in your driveway.
For module work generally, our car computer module programming guide lays out scope, and where a module has suffered moisture damage the water-damaged modules guide covers what is realistically recoverable.
Common cases we see in Southlake
Range Rover and Range Rover Sport
The vehicles most likely to arrive with a stack of fobs already purchased. Owners have usually been through the parts-swapping cycle before someone diagnoses the antenna. Frustrating, expensive and entirely avoidable with one free two-fob test.
Discovery Sport and Evoque
The highest-volume keyless complaints on our schedule simply because there are more of them here. The pattern is textbook: gradual onset, positional failure, both fobs affected.
Jaguar F-Pace and XF
Same underlying keyless architecture family, same failure modes. Jaguar owners are slightly more likely to have had a dealer diagnosis already, which is useful context we are happy to work from rather than repeat.
Vehicles that sit
A Southlake weekend car that sits three weeks arrives with a flat vehicle battery, a tired fob cell and a keyless system behaving strangely. Low system voltage produces symptoms that mimic module failure. Charge the vehicle properly and retest before condemning anything — we say this on the phone and it resolves a meaningful number of calls at no charge.
Aftermarket electronics
A poorly installed remote start, alarm or tracker tapped into the wrong circuit is a recurring cause of keyless strangeness on these vehicles. Our remote start immobilizer problems guide covers what to look for, and it is always worth mentioning any aftermarket install when you call.
Frequently Asked Questions
Why does my Land Rover only detect the key sometimes?
Intermittent detection that depends on where the fob is sitting points at a keyless antenna or the keyless module rather than the key. The confirming test is free: if a second known-good fob fails the same way, the fault is on the vehicle side and another fob will not fix it.
What is the RFA module on a Land Rover or Jaguar?
The remote function and keyless module — the control unit that manages keyless entry and push-button start, driving the antennas around the vehicle that detect your fob and authorize doors and starting. When it or one of its antennas degrades, key detection becomes intermittent.
Can a locksmith program a keyless module, or is that dealer work?
Many are programmable through the diagnostic port and can be done at your location. Some require the module removed and worked directly, and certain newest-generation vehicles require manufacturer authorization no independent holds. We establish which from your VIN before dispatch.
I already bought two new fobs and nothing changed. What now?
That result is itself the diagnosis — two new fobs failing identically is close to conclusive evidence of a vehicle-side fault. The next step is antenna and module diagnosis, not a third fob. Bring us what you have and we will work from there.
How much does keyless system diagnosis cost?
Diagnosis runs $120 to $280 depending on how much isolation the symptom requires. It is money well spent against the alternative, which is buying fobs and modules on guesswork. We quote any repair only after the fault is identified.
If your Land Rover or Jaguar sees the key most of the time, stop buying fobs and let us diagnose it. Call or text (972) 573-7978.
Written by the Southlake TX Locksmiths Automotive Locksmith Team — mobile automotive locksmith service across Southlake, Colleyville, Keller, Grapevine, Westlake and the DFW northeast.