Vehicle Immobilizers (SKIM/PATS/SKREEM)

The immobilizer is the vehicle's anti-theft brain. It verifies your key or fob before it will let the engine start. You'll see it named differently by brand — SKIM or SKREEM on Chrysler, Dodge, Jeep, and Ram; PATS on Ford, Lincoln, and Mercury; PassKey or PassLock on GM.

A no-start with the security or theft light flashing is the classic sign, along with a key that's suddenly not recognized or a "vehicle immobilized" message. Because it's a security part, the engine may crank but won't fire, or won't crank at all, until the system sees a valid key.

Yes — always. The module has to be married to your VIN and your keys relearned, which is done by a dealer or an automotive locksmith with the right tool. Buy the correct OEM part number, then have it programmed. Message us your VIN and we'll confirm the exact part before you buy.

This is a security part tied to your specific keys — there's no aftermarket equivalent. A tested OEM module with the correct part number, programmed to your vehicle, is the correct fix. Every unit we sell is pulled, inspected, and tested for functionality before listing.

Immobilizers are factory anti-theft systems that prevent the engine from starting unless a correctly coded key is present. Different manufacturers call them different things — Ford calls theirs PATS (Passive Anti-Theft System) or SecuriLock; Chrysler/Dodge/Jeep call theirs SKIM (Sentry Key Immobilizer Module) or SKREEM (Sentry Key Remote Entry Module). The principle is the same across all of them.

A radio-frequency transponder in the key sends a unique code to a receiver in the vehicle. The receiver passes that code to the immobilizer module, which compares it against the keys it has programmed. If the code matches, the module signals the PCM to enable the fuel injectors and starter. If it doesn't match, the engine won't start — even if the key physically turns in the ignition.

That last part is why a failing immobilizer module looks like a dead engine, not a security alert.

The signature symptom is a no-start condition with the security or theft indicator behaving abnormally — typically rapid flashing instead of the normal brief flash at key-on. Other patterns:

• Engine cranks but won't start, and the security light flashes rapidly or stays on. The starter is firing, but the PCM never gets the "valid key" signal.
• Vehicle starts and immediately stalls. On Ford PATS, this can indicate a PCM/PATS communication issue — the engine runs for about a second on initial fuel, then the immobilizer fails to validate and shuts the injectors off.
• Intermittent no-starts that resolve after waiting or retrying. Sometimes a module that's losing communication with the antenna or the PCM presents this way before failing fully.
• Body/Network DTCs pointing at the immobilizer module itself. Codes like B2229 (SKIM/SKREEM internal), or PATS-specific B-codes in the B1xxx and B2xxx ranges, are signals the module has self-diagnosed an internal fault.

Worth ruling out first: dead key transponder battery (on systems that use one), key damage, or a foreign object near the key (metallic keychains, other transponders) interfering with the transmission. These are easier and cheaper checks than replacing a module.

Almost always, yes — and the programming requirements vary by manufacturer and platform.

• Ford PATS: Replacement requires a "parameter reset" or relearn procedure using a scan tool with PATS programming capability (factory IDS, FORScan with extended license, or equivalent professional-grade tool). The exact procedure depends on which PATS type your vehicle uses — Ford has used at least seven variants (Types A through G) with the security logic living in different modules depending on platform.
• Chrysler/Dodge/Jeep SKIM/SKREEM: Most replacement modules require programming to match the vehicle's PCM VIN and to learn the existing keys. Some modules sold in the aftermarket arrive pre-programmed for plug-and-play installation; others require dealer or independent-shop programming. The listing for each unit specifies which.
• All systems: "Plug-and-play" claims should be treated carefully. Some modules genuinely arrive ready to install on specific platforms; many require at least a key-relearn procedure even when no full programming is needed.

Each immobilizer listing in our shop specifies what programming will be required for that specific unit. If you're not sure what your install will need, send your VIN and the part number you're looking at — Hubes will tell you straight.

Sometimes — depends on the platform, the tools you have, and what "programming" means in your case.

Adding a spare key when you already have working keys is often a DIY procedure on older systems (key-on cycles in a specific sequence). The owner's manual or the service procedure for your platform documents the steps if it's possible.

Replacing the module itself is a different category of work. Module-level programming generally requires:

• A scan tool with the right software for your platform (FORScan for Ford, scan tool with Chrysler-specific software for SKIM/SKREEM, or equivalent professional-tier tool)
• Stable battery voltage during programming (a battery maintainer is recommended — voltage drops mid-programming can corrupt the module)
• The correct procedure for your specific PATS type or SKIM generation

This is doable for shops and serious DIYers with the right equipment. It's not the kind of job you can complete with a generic OBD-II reader. If you don't have the tooling, the practical answer is dealer programming or an independent shop with immobilizer-capable diagnostics.

OEM modules are made by the original manufacturer (Mopar for Chrysler/Dodge/Jeep, Ford/Motorcraft for Ford) and use the security protocols and key-coding systems your vehicle's PCM expects. Aftermarket immobilizer alternatives include rebuilt modules, universal-fit substitutes, or "bypass" devices that disable the immobilizer function entirely.

Two things to weigh on aftermarket immobilizer parts specifically:

• Communication protocol matching. Immobilizer modules talk directly to the PCM over the vehicle's communication network. OEM modules use the exact protocol the PCM expects; aftermarket substitutes can introduce communication faults that don't show up until you try to start.
• Bypass solutions trade security for convenience. PATS bypass kits and SKIM delete modules will get the vehicle running, but they remove the factory anti-theft protection — which can affect insurance and resale.

Every immobilizer module Hubes Hub sells is OEM, sourced from a documented vehicle, and bench-tested before listing. See Parts, condition & testing for the Grade A — Tested standard.

Within the same generation of a platform, sometimes — but the part number is the deciding factor, not the year on the listing. Immobilizer modules supersede across model years when the underlying hardware and software stay the same. Different generations (Ford PATS Type B vs Type C, for example, or different SKIM revision levels) use entirely different modules even on vehicles that look identical from the outside.

Two-step verification:

1. Compare the part number on your old module to the OEM Part Number on the listing. Exact match means exact fit. "Supersedes to" or "replaces" references also indicate a fit.
2. If the part numbers don't obviously match, send your VIN. Manufacturer supersession can route a single newer part number to multiple older platforms; we'll confirm the right unit for your build.

See Fitment & vehicle compatibility for the full process.

Coverage varies as inventory turns. Hubes Hub stocks immobilizer modules across SKIM/SKREEM, PATS, and equivalent systems on most domestic platforms. The live listing on the Vehicle Immobilizers collection shows what's in stock right now.

If you don't see your vehicle, send your VIN and the part number off your old module if you have it. Hubes can tell you whether something fitting your build is coming through the bay.