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Diagnostic reference

Anti-theft & module failure guides, by make.

Immobilizer and anti-theft systems vary a lot by manufacturer, and by era within the same manufacturer. Find your make below for the system it uses, the symptoms that usually mean that system is failing, and how we diagnose and fix it — on-site or by mail.

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Featured guides

The four most common calls.

PATS — Passive Anti-Theft System

Ford, Lincoln & Mercury

Ford's PATS ties the ignition key's embedded chip to the PCM (and on many models, the BCM). It's designed to keep the engine from starting unless the correct coded transponder is present.

Common symptoms

  • Security light flashes rapidly and the engine cranks but won't start
  • Vehicle starts, runs briefly, then shuts off
  • New keys won't program, or "too many keys" errors
  • All keys lost — no working transponder key on hand

How we fix it

We read PATS status directly from the PCM/BCM, cut and program new keys to match, and — when the module itself has failed rather than just the key data — program or replace the BCM/PCM on-site or as a mail-in repair.

Common ignition & lock failures

  • Ignition lock cylinder tumblers wearing out — key sticks or needs wiggling to start
  • Steering column lock/interlock actuator failing — key turns but the column stays locked, or it won't release from Park
  • Key blade snapping off in a worn cylinder
  • Door and trunk lock cylinders seizing from age or lack of lubrication
Start a Ford repair
PASSLOCK & VATS

GM — Chevrolet, GMC, Buick, Cadillac

Older GM vehicles used VATS, a resistor pellet embedded in the key blade. Most vehicles from the late 1990s onward moved to Passlock, which reads a code from the ignition lock cylinder instead of the key itself.

Common symptoms

  • Security light stays on solid or flashes; car cranks but won't fire
  • Intermittent no-starts that seem to "fix themselves"
  • Car starts, stalls after a few seconds, theft light flashing
  • Ignition lock cylinder worn and no longer reading correctly

How we fix it

We test the Passlock sensor and BCM communication, relearn the security system where the hardware is still good, and repair or replace the lock cylinder or BCM when it isn't.

Common ignition & lock failures

  • Worn ignition lock cylinder — the most common root cause of a Passlock fault, not the module itself
  • Key turning loosely or not fully engaging the tumblers
  • Column lock mechanism sticking, especially on trucks and SUVs carrying heavy key rings
  • Snapped key in the cylinder from a worn tumbler pack
Start a GM repair
SKIM / SKREEM & TIPM

Chrysler, Dodge, Jeep & RAM

Stellantis brands use a Sentry Key Immobilizer Module (SKIM or SKREEM) to authorize the key, and route a lot of body electrical functions — including key/fob logic — through the TIPM (Totally Integrated Power Module), which is a well-known failure point on its own.

Common symptoms

  • Key fob stops working for locks, but the vehicle still starts (or vice versa)
  • No-crank, no-start with a good battery
  • Random electrical faults — wipers, fuel pump relay, or interior lights acting up
  • Fobs won't program, or program then stop working days later

How we fix it

We separate a TIPM problem from a SKIM problem before touching anything, since they're often confused. TIPM repair is one of our most common mail-in jobs.

Common ignition & lock failures

  • Ignition switch electrical contacts wearing with age — intermittent accessory power or no-crank on older models
  • Lock cylinder tumbler wear making the key hard to turn
  • Steering column lock sticking, particularly on higher-mileage trucks and Jeeps
  • Broken key extraction from a worn cylinder
Start a Stellantis repair
Toyota Immobilizer / Smart Key

Toyota & Lexus

Toyota's immobilizer checks the transponder chip against the ECU, and on Smart Key–equipped models, against a certification ECU as well. It's a reliable system, but registration is picky about sequence and can lock owners out after a failed attempt.

Common symptoms

  • Master warning light with an immobilizer or key icon
  • Smart key detected but push-button start won't engage
  • Spare key never registered, and dealer wants all keys present to add one
  • All keys lost on a Smart Key vehicle

How we fix it

We can register additional keys without every existing key present in most cases, and handle all-keys-lost by working directly with the certification ECU.

Common ignition & lock failures

  • Ignition cylinder tumbler wear at high mileage — key sticking or difficult to turn
  • Steering lock actuator faults on Smart Key models — won't release from Park or won't unlock the wheel
  • Door lock cylinder wear on older models without keyless entry
  • Broken key extraction from a worn cylinder
Start a Toyota repair
Full A–Z reference

Every major make, one page.

Tap a make for its anti-theft system and the symptoms we see most.

Acura Immobilizer (shared w/ Honda)

Acura shares its immobilizer architecture with Honda — transponder key data checked against the PCM.

  • Security light flashing, no-start
  • Key recognized but won't crank
  • Push-button start models: fob detected but won't authorize

Ignition & lock:

  • Worn ignition tumblers causing a hard-to-turn key
  • Steering column lock sticking on high-mileage models
Start a repair →
Audi VAG immobilizer

Audi's immobilizer data lives in the ECU (and on newer models, the instrument cluster), tied to the key's transponder.

  • "Key not recognized" despite a genuine key
  • No-start after a battery replacement or ECU swap
  • All keys lost, especially on used imports without service history

Ignition & lock:

  • Worn lock cylinder tumblers making the key hard to turn
  • Electronic steering lock (ELV) faults preventing start
Start a repair →
BMW EWS (older) / CAS (newer)

Older BMWs use EWS (Elektronische Wegfahrsperre); most 2004+ models use CAS (Car Access System), which also controls a lot of general body electronics.

  • "Vehicle not able to start" message, key detected
  • CAS module failing to communicate — multiple warning lights at once
  • Key fob battery good, but proximity start won't engage

Ignition & lock:

  • Steering lock actuator failures tied to EWS/CAS, common on older 3 and 5 Series
  • Worn ignition switch contacts
Start a repair →
Buick Passlock / GM security

Buick runs the same GM Passlock/BCM-based security architecture as Chevrolet and GMC.

  • Theft light on, engine cranks but doesn't fire
  • Security relearn required after BCM or ignition switch work

Ignition & lock:

  • Worn ignition lock cylinder feeding a bad Passlock signal
  • Column lock sticking, especially on higher-mileage models
Start a repair →
Cadillac Passlock / GM security

Same GM security family as the rest of the brand's lineup, with additional proximity/push-button variants on later models.

  • No-start with security light active
  • Proximity fob detected, push-button start won't authorize

Ignition & lock:

  • Worn lock cylinder tumblers on non-push-button models
  • Column lock/actuator sticking on push-button models
Start a repair →
Fiat Immobilizer (Stellantis-shared / Body Computer)

US-market Fiat 500, 500L, and 500X share Stellantis's SKIM-linked immobilizer architecture with Chrysler and Dodge. Older and European-market models instead use Fiat's own Body Computer, which handles immobilizer duties alongside general body electronics.

  • Security light flashing, engine cranks but won't start
  • Key recognized at the door but the immobilizer won't release for start
  • All keys lost — parts and programming support can be limited given lower US sales volume

Ignition & lock:

  • Worn ignition lock barrel causing a hard-to-turn key
  • Steering column lock sticking on older models
Start a repair →
Genesis Immobilizer (shared w/ Hyundai)

Genesis uses Hyundai Motor Group's immobilizer and smart key architecture.

  • Smart key detected, engine won't start
  • All keys lost on a push-button model

Ignition & lock:

  • Steering/ignition lock actuator faults on push-button models
  • Worn door lock cylinders
Start a repair →
GMC Passlock / GM security

Same GM Passlock/BCM security system used across Chevrolet, Buick, and Cadillac.

  • Cranks but won't start, theft light flashing
  • Worn ignition lock cylinder losing its Passlock signal

Ignition & lock:

  • Same GM lock cylinder wear pattern as Chevrolet and Buick
  • Snapped key in a worn cylinder
Start a repair →
Honda Immobilizer / PCM-linked

Honda's immobilizer checks the key's chip against the PCM; later models add a separate keyless module for proximity fobs.

  • Security light flashing, won't crank or won't stay running
  • Keyless fob detected but start button unresponsive

Ignition & lock:

  • Worn tumbler pins causing key sticking
  • Steering column lock sticking on older Civics and Accords
Start a repair →
Hyundai Immobilizer / Smart Key

Hyundai's immobilizer and smart key system authorizes start through the body control module. Some model years also received manufacturer security software updates addressing theft vulnerabilities — worth checking your specific VIN's campaign status.

  • Smart key detected, no-start
  • All keys lost
  • Ignition switch worn on older non-push-button models

Ignition & lock:

  • Worn ignition switch contacts on older non-push-button models
  • Steering lock actuator faults on Smart Key models
Start a repair →
Infiniti NATS (shared w/ Nissan)

Infiniti uses Nissan's NATS (Nissan Anti-Theft System) immobilizer architecture.

  • Security light on dash, no-start
  • Intelligent key detected but push-button start fails

Ignition & lock:

  • Steering lock actuator faults tied to NATS/Intelligent Key
  • Worn door lock cylinders
Start a repair →
Jaguar Immobilizer / Smart Key (KVM-linked)

Jaguar ties key authorization to the Key Vehicle Module (KVM) working with the BCM — proximity keys and traditional transponders both check in through the same chain.

  • Proximity key detected, engine won't start
  • Security/immobilizer light on dash, cranks but won't fire
  • All keys lost, especially on older imports without full service history

Ignition & lock:

  • Worn ignition switch or lock barrel on older non-keyless models
  • Steering lock actuator faults preventing start
Start a repair →
Jeep SKIM / SKREEM & TIPM

Same Stellantis architecture as Chrysler, Dodge, and RAM — see the featured Chrysler guide above for the full breakdown.

  • Fob works for locks, not for start (or vice versa)
  • No-crank with a known-good battery

Ignition & lock:

  • Ignition switch contact wear on older models
  • Steering column lock sticking, common on high-mileage Wranglers
Start a repair →
Kia Immobilizer (shared w/ Hyundai)

Kia shares Hyundai Motor Group's immobilizer and smart key architecture.

  • Smart key detected, engine won't start
  • All keys lost on a push-button model

Ignition & lock:

  • Worn ignition switch on older models
  • Steering lock actuator faults on Smart Key models
Start a repair →
Land Rover Immobilizer / Smart Key (shared w/ Jaguar)

Land Rover shares Jaguar's KVM/BCM-linked immobilizer architecture. Range Rover and Discovery models are especially known for BCM-to-KVM communication faults as they age.

  • Proximity key or fob detected, engine won't start
  • Intermittent no-start that seems to "fix itself" after several tries
  • All keys lost

Ignition & lock:

  • Worn lock cylinders on older Defenders and Discoveries
  • Steering lock actuator faults preventing start
Start a repair →
Lexus Immobilizer / Smart Key (shared w/ Toyota)

Lexus shares Toyota's immobilizer and Smart Key certification ECU architecture — see the featured Toyota guide above.

  • Master warning light, immobilizer icon
  • Smart key detected but push-button start won't engage

Ignition & lock:

  • Ignition cylinder tumbler wear at high mileage
  • Steering lock actuator faults on Smart Key models
Start a repair →
Lincoln PATS (shared w/ Ford)

Lincoln uses Ford's PATS system — see the featured Ford guide above for full symptom detail.

  • Security light flashing, cranks but won't start
  • All keys lost

Ignition & lock:

  • Same PATS-linked ignition cylinder wear as Ford
  • Steering column lock/interlock actuator failures
Start a repair →
Mazda Immobilizer / Advanced Keyless

Mazda's immobilizer authorizes through the PCM, with a separate keyless module on Advanced Keyless-equipped models.

  • Security light flashing, no-start
  • Keyless entry works, engine start doesn't

Ignition & lock:

  • Worn tumbler pins causing key sticking
  • Steering column lock sticking on higher-mileage models
Start a repair →
Mercedes-Benz EZS / DAS

Mercedes uses EZS (electronic ignition switch) working with the Drive Authorization System (DAS) to verify the key before allowing start.

  • "Insert key" or "no key detected" with the correct key present
  • EZS module communication faults after a battery event

Ignition & lock:

  • EZS-linked steering lock faults
  • Worn ignition lock barrel

ESL (Electronic Steering Lock) failures:

The ESL (also called ELV) is a well-known Mercedes wear point, especially on W203, W211, and W219-era models, and fails independently of a good key or battery.

  • Steering wheel stays mechanically locked even though the key is recognized
  • "ESL/ELV" or steering lock fault message on the dash
  • Car won't shift out of Park because the ESL hasn't confirmed unlocked status
  • Intermittent fault that comes and goes with steering wheel movement
Start a repair →
MINI CAS / FEM-BDC (BMW-based)

Modern MINI shares BMW's access-control architecture, from CAS on earlier models to FEM/BDC modules on later ones.

  • Key fob detected, "vehicle not able to start"
  • Multiple unrelated warning lights after a module fault

Ignition & lock:

  • Steering lock actuator faults shared with the BMW platform
  • Worn lock cylinders
Start a repair →
Mitsubishi Immobilizer

Mitsubishi's immobilizer checks the key transponder against the ECU before allowing start.

  • Security light flashing, cranks but won't start
  • All keys lost

Ignition & lock:

  • Worn tumbler pins causing key sticking
  • Steering column lock sticking
Start a repair →
Nissan NATS

Nissan's NATS (Nissan Anti-Theft System) checks the key's transponder ID against the BCM/ECU before authorizing start.

  • Security light on, cranks but won't fire
  • Intelligent key detected but push-button start fails
  • All keys lost

Ignition & lock:

  • Steering lock actuator faults tied to NATS/Intelligent Key
  • Worn door lock cylinders
Start a repair →
RAM SKIM / SKREEM & TIPM

Same Stellantis architecture as Chrysler, Dodge, and Jeep — see the featured Chrysler guide above. TIPM failure is especially common on RAM trucks.

  • No-crank, no-start with a good battery
  • Random electrical faults tied to the TIPM

Ignition & lock:

  • Ignition switch contact wear on older trucks
  • Steering column lock sticking at high mileage

Fleet spotlight: ProMaster & ProMaster City

Unlike the 1500/2500/3500 pickups, ProMaster is a rebadged Fiat Ducato and ProMaster City a rebadged Fiat Doblo — both run Fiat-derived immobilizer and body electronics rather than the SKIM/TIPM architecture used across the rest of the RAM lineup. That matters for fleets: a technician assuming standard RAM logic will diagnose the wrong system.

  • Immobilizer tied to a Fiat-style Body Computer, not the TIPM
  • High-cycle commercial use accelerates ignition lock cylinder and door lock wear across multi-driver fleets
  • All-keys-lost and add-a-key jobs need Fiat-specific programming procedures, not RAM truck ones
  • Parts and key stock availability is more limited than for mainstream RAM trucks — worth confirming before scheduling
Start a repair →
Sprinter EZS / DAS (Mercedes-Benz-based)

The Sprinter has been sold under several badges over the years — Dodge Sprinter in the US from 2003–2006, Freightliner Sprinter for fleet channels, and Mercedes-Benz Sprinter since 2007 — but the underlying engineering, including the key and immobilizer system, has always been Mercedes-Benz's. It runs the same EZS (electronic ignition switch) and DAS (Drive Authorization System) architecture as Mercedes-Benz passenger vehicles.

  • "Insert key" or "no key detected" message with the correct key present
  • No-crank, no-start with a good battery
  • EZS module communication faults after a battery event or jump-start
  • All keys lost — common on fleet vans passed between drivers with no spare tracked down

Ignition & lock:

  • ESL/ELV (electronic steering lock) faults — same wear point as Mercedes-Benz cars, steering stays mechanically locked despite a recognized key
  • Worn ignition lock barrel from high-cycle fleet use
  • "ESL/ELV" or steering lock fault message on the dash

Badge history matters for parts lookup

Whatever badge is on the steering wheel or grille, VIN and module lookups should be run under Mercedes-Benz/Freightliner records — searching by "Dodge" on a 2003–2006 van, for example, will miss the correct immobilizer data.

Start a repair →
Subaru Immobilizer / Keyless Access

Subaru's immobilizer authorizes through the ECU, with a separate keyless module on push-button models.

  • Security light flashing, no-start
  • Key fob detected but push-button start won't engage

Ignition & lock:

  • Worn tumbler pins on non-push-button models
  • Steering lock actuator faults on push-button models
Start a repair →
Tesla Key card / phone key + gateway module

Tesla doesn't use a traditional immobilizer — access and start authorization run through key cards, phone-as-key BLE pairing, and the vehicle's central gateway module.

  • Phone key not detected/pairing intermittently
  • Key card works at the door but not for drive authorization
  • Gateway module faults after a 12V battery event

Door & latch mechanisms:

  • No traditional ignition lock — but presenting/retracting door handle motors are a common failure point
  • Charge port and frunk/trunk latch actuator faults
Start a repair →
Volkswagen VAG immobilizer

VW shares Audi's VAG immobilizer architecture — key data checked against the ECU or instrument cluster.

  • "Key not recognized" with a genuine key
  • No-start after a battery or ECU replacement

Ignition & lock:

  • Worn lock cylinder tumblers making the key hard to turn
  • Electronic steering lock (ELV) faults preventing start
Start a repair →
Volvo CEM-linked immobilizer

Volvo routes key authorization through the Central Electronic Module (CEM), which is also a well-known failure point for unrelated electrical gremlins.

  • No-start with a key that works fine on the doors
  • Multiple dash warnings tied to a failing CEM
  • Water intrusion damage to the CEM (mounted near the windshield on many models)

Ignition & lock:

  • Worn ignition lock barrel
  • Steering lock actuator issues tied to a failing CEM
Start a repair →
Two wheels, different systems

Motorcycle key & lock services.

Motorcycles don't work like cars — one key usually runs the ignition, fork lock, seat lock, and saddlebags all at once, and not every bike has an electronic immobilizer to worry about. Here's how we handle rekeying, all-keys-lost, and the failures we see most.

01

Rekeying

Most motorcycles run one key across the ignition, fork lock, seat lock, and saddlebags or panniers.

  • Cut a full matching set from a single working key
  • Rekey from the lock cylinders themselves if no key is available
  • Common for used-bike buyers who only got one key at purchase
02

All Keys Lost

No working key means addressing both the mechanical lock and, on newer bikes, the security chip.

  • Read the bike's immobilizer/ECU directly where one exists
  • Cut new keys to fit the ignition and fork lock
  • Purely a mechanical lock job on older, non-immobilizer bikes
  • Same ownership verification as car all-keys-lost orders
03

Common Issues

What we see most, across nearly every make.

  • Fork lock seized from rust or water — bikes stored outside
  • Key snapped off in the ignition or fork lock (thinner blades than car keys)
  • Ignition switch contacts worn, causing intermittent power loss
  • Seat or saddlebag lock cylinders seized from infrequent use
By manufacturer

Immobilizer systems, by brand.

Harley-Davidson Smartkey / H-D1 (2014+)

2014-and-newer touring and Softail models use Harley's Smartkey immobilizer with color-coded fobs. Earlier models use a simple mechanical ignition and fork lock with no electronic immobilizer.

  • Security indicator flashing, engine cranks but won't start (Smartkey models)
  • Fob detected but bike won't start
  • All keys lost

Ignition & lock:

  • Worn fork lock tumblers on pre-2014 models
  • Ignition switch contacts wearing, causing intermittent power loss
Start a repair →
Honda H.I.S.S. (Honda Ignition Security System)

H.I.S.S. checks the key's transponder against the ECU on most modern Honda models before allowing start.

  • Red immobilizer indicator flashing, cranks but won't start
  • Key recognized but the bike stalls immediately after starting
  • All keys lost

Ignition & lock:

  • Worn ignition and fork lock tumblers
  • Key sticking or hard to turn
Start a repair →
Yamaha YIS (Yamaha Immobilizer System)

Higher-end and sport models run YIS; many cruisers and smaller-displacement bikes use a simple mechanical lock with no immobilizer at all.

  • Immobilizer indicator flashing, no-start (YIS models)
  • All keys lost on YIS-equipped bikes

Ignition & lock:

  • Fork lock seizing from corrosion
  • Worn ignition tumblers
Start a repair →
Kawasaki KIPASS (select models) / Standard Immobilizer

Select higher-end models use KIPASS (Kawasaki Intelligent Proximity Activation Start System); most others use a standard transponder immobilizer.

  • No-start even with the fob nearby (KIPASS models)
  • Immobilizer indicator flashing, cranks but won't start

Ignition & lock:

  • Worn ignition switch contacts
  • Fork lock tumbler wear
Start a repair →
Suzuki Standard Transponder Immobilizer

Most modern Suzuki models use a standard transponder immobilizer checked against the ECU.

  • Security light flashing, no-start
  • All keys lost

Ignition & lock:

  • Worn tumblers causing key sticking
  • Fork lock wear on higher-mileage bikes
Start a repair →
Ducati Marelli ECU-linked immobilizer

Ducati's immobilizer is tied to the Marelli ECU on most modern models. Lower US sales volume can mean thinner local parts and key stock support.

  • Dash immobilizer icon, cranks but won't start
  • All keys lost — often needs more lead time on parts

Ignition & lock:

  • Worn ignition barrel
  • Fork lock seizing
Start a repair →
BMW Motorrad Keyless Ride (select models) / Immobilizer

Higher-end touring models with Keyless Ride share access-control concepts with BMW's automotive CAS system; most other models use a standard transponder immobilizer.

  • "Key not recognized" with a genuine key
  • Keyless Ride fob detected but bike won't start

Ignition & lock:

  • Worn ignition lock barrel
  • Steering lock actuator faults on Keyless Ride models
Start a repair →
Triumph Standard Transponder Immobilizer

Modern Triumph models run a standard transponder immobilizer checked against the ECU.

  • Immobilizer indicator flashing, no-start
  • All keys lost

Ignition & lock:

  • Worn ignition and fork lock tumblers
  • Fork lock seizing on bikes stored outdoors
Start a repair →
KTM Standard Transponder Immobilizer

Modern KTM models use a standard transponder immobilizer. Off-road and dual-sport models see more dirt and water exposure at the ignition barrel.

  • Immobilizer indicator flashing, no-start
  • All keys lost

Ignition & lock:

  • Ignition barrel wear accelerated by dirt and water exposure
  • Fork lock sticking on off-road models
Start a repair →
Indian Motorcycle Standard Transponder Immobilizer

Modern Indian models (Polaris-owned) use a standard transponder immobilizer checked against the ECU.

  • Security light flashing, no-start
  • All keys lost

Ignition & lock:

  • Worn ignition switch
  • Fork lock wear on higher-mileage bikes
Start a repair →
Call about a motorcycle Or start a mail-in order
Don't see your exact symptom?

Call it in — we'll tell you what it is.

These guides cover the patterns we see most often. Every vehicle and fault combination is a little different, and a two-minute call usually narrows it down faster than guessing from a symptom list.

Call (865) 405-5359 Or start a mail-in order
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