Ignition Fixed But the Car Still Won't Start

As of August 2026, when a repaired ignition still will not start the car in Arlington, the single most useful piece of information is whether the engine cranks — that one observation splits the problem between a locksmith and a mechanic before either of them charges you. Arlington TX Locksmith diagnoses the immobilizer and key side on-site and tells you plainly when the fault is not ours. Call or text (817) 330-5762. This guide walks the four things that all have to go right, in order.

Four gates, not one

"The car won't start" describes a symptom, not a fault. Between the key in your hand and an engine at idle there are four independent gates, and a repaired ignition only clears the first.

Gate one — mechanical. The cylinder rotates, or on a push-button vehicle the start authorisation is granted. This is what an ignition repair fixes.

Gate two — electrical. Turning the key actually energises the starter circuit. Battery voltage, grounds, the neutral safety switch and the starter itself all live here.

Gate three — security. The immobilizer reads the chip in your key, decides it is legitimate, and tells the engine controller to permit fuel and spark. Fail this gate and the engine spins enthusiastically forever without firing.

Gate four — the engine itself. Fuel, spark, air, compression. Ordinary mechanical work.

An ignition repair that succeeds mechanically and leaves the car dead means one of the other three gates is closed. Nearly everything else in this guide is about identifying which.

The thirty-second test that splits the problem

Sit in the vehicle, watch the instrument cluster, and turn the key or press start. What happens next puts you in one of three buckets.

Bucket A — strong crank, never fires, security telltale lit or blinking. The starter is doing its job and the engine controller is refusing to let the engine run. This is gate three. It is a key, immobilizer or programming fault, and it is squarely locksmith territory.

Bucket B — no crank at all, or a single click, or a slow laboured crank. The starter is not being energised properly. This is gate two: battery, terminals, grounds, starter solenoid, neutral safety switch or a supply fault. This is mechanic territory, and no key will fix it.

Bucket C — cranks and fires briefly, then dies within a second or two. Classic immobilizer partial-authorisation on some platforms, but also a genuine fuel or ignition-system fault. This bucket needs a real diagnosis, and it is the one where guessing wastes the most money.

That is the entire triage. Everything after this is detail.

Bucket A: the immobilizer side

If you are in bucket A, here is what is actually happening and what gets checked.

The transponder chip. Every key for a vehicle from roughly 1998 onward carries a passive chip in the head. It has no battery — it is energised by an antenna ring around the ignition and answers with a code. If the chip has failed, cracked or was never a genuine match, the answer never arrives.

The antenna ring. The coil surrounding the lock cylinder is a wear item, and it lives exactly where a cylinder repair happens. A ring that was disturbed, unplugged or damaged during a cylinder replacement produces a car that cranked fine before the repair and refuses after. This is one of the most common versions of "it was worse after I fixed it," and it is not mysterious — it is a connector.

The relearn that never happened. Several platforms tie the immobilizer to the ignition assembly. Change the assembly and the system needs a relearn procedure before it will accept any key at all, including the ones that worked yesterday. If a repair ended with the car dead and a security light, this is the first thing to check, and it is a routine on-site procedure.

A cheap key with the wrong chip. Aftermarket keys vary enormously. A key with a mismatched or low-quality chip can program successfully on a warm afternoon and then fail intermittently once temperatures change. If the no-start started within weeks of a bargain replacement key, testing with a known-good key is fast and conclusive.

Our guide to whether a locksmith can program your key fob covers which brands and systems are within mobile scope, and GM PassLock and VATS no-starts covers one of the oldest and most misdiagnosed versions of this fault.

Vehicle owners should confirm whether an open safety recall applies to their specific vehicle, since some no-start and ignition conditions have been the subject of manufacturer recalls. — NHTSA

Bucket B: why this is not a key problem

The most expensive mistake in this whole category is buying a key for a bucket-B car.

If the engine does not crank, the immobilizer has not even entered the conversation. On most vehicles the immobilizer permits or blocks fuel and spark — the starter still turns the engine over either way. That is precisely why a strong crank with no start is such a clean immobilizer signature, and why no crank means the fault is upstream of anything a key touches.

Common bucket-B causes, roughly in order of frequency:

Battery. A battery with enough charge to light the dash and not enough to turn a starter is extremely common, particularly on Texas summer heat cycling. Dash lights are not a battery test.
Terminals and grounds. Corrosion at a battery post or a chassis ground produces a no-crank that mimics a dead starter exactly.
Neutral safety or clutch switch. The vehicle believes it is in gear. Try starting in Neutral as well as Park — if Neutral works, the switch is the fault.
Starter or solenoid. A single loud click, or silence with good battery voltage.

If the vehicle turns out to have a dead 12-volt battery and is also locked, that combination has its own complications on push-button vehicles — covered in our guide to a push-start car with a dead 12V battery and the doors locked.

What it costs in Arlington

Figures reflect the Arlington area as of August 2026 for the locksmith-side work. Mechanical repairs in bucket B are a different trade and are not quoted here.

Job	When it applies	Cost Range (Arlington)	Time On-Site
Immobilizer diagnosis — is the key being accepted?	Bucket A, cause unknown	$85 – $165	20 – 45 min
Immobilizer relearn after ignition work	Security light after a repair	$80 – $170	20 – 45 min
Fresh key cut to code and programmed	Chip failed or key is a poor match	$95 – $180	20 – 40 min
Smart or proximity key replaced and programmed	Push-button start vehicles	$180 – $400	30 – 60 min
Antenna ring diagnosis and reconnection	No-start immediately after a cylinder job	$85 – $190	30 – 60 min
All keys lost, immobilizer originated to a new key	No working key exists	Quote required	60 – 150 min

You get a firm total before work starts, including the trip charge, rather than a number that grows once the panel is off.

Before authorising work, get the full price in advance and confirm the company is properly licensed in your state. — Federal Trade Commission

The boundary — and why we tell you where it is

There is a temptation in this trade to sell a key to every no-start, because a key is a product with a price and a diagnosis is just time. We would rather do the diagnosis and tell you it is a starter.

The honest boundary looks like this. Ours: keys, chips, transponder programming, immobilizer relearns, antenna rings, ignition cylinders and modules, all-keys-lost origination. Not ours: batteries, starters, alternators, fuel pumps, injectors, timing, compression, wiring harness faults, anything requiring a lift.

There is also a band at the edges — newest-generation vehicles and certain premium European platforms where the security architecture is gated to the manufacturer. On those, the right answer is a tech confirming your exact vehicle and model year before anything is promised, not a confident quote over the phone. Our post on Mercedes EIS and electronic steering-lock no-starts is an example of a platform where that boundary matters.

What to have ready when you call

Five answers turn a diagnostic visit into a repair visit.

Year, make and model. The immobilizer architecture is entirely platform-specific.
Which bucket you are in. Cranks and does not fire, or does not crank at all. This is the single most useful thing you can tell us.
What the security telltale is doing. Off, steady, or blinking — all three mean different things.
What changed recently. An ignition repair, a new key, a battery replacement, a break-in attempt. Timing is diagnostic.
Whether another key behaves differently. As always, the spare is the fastest test in the business.

If the vehicle is stranded somewhere it should not stay — a shoulder on the Highway 360 corridor, a lot near Lake Arlington after dark — lead with that so the call is prioritised properly. Our guide to roadside lockouts on I-20 and 360 covers staying safe while you wait.

Frequently Asked Questions

The ignition was repaired and the car still won't start. What now?

Separate the symptom first. If the engine cranks strongly and never fires with a security light lit, that is an immobilizer or key-credential fault and it is locksmith territory. If nothing happens at all when the key is turned, that is more likely a starter, battery or supply problem and it belongs with a mechanic.

What does a blinking security light actually mean?

It means the vehicle's immobilizer did not accept the key credential and the engine controller is withholding fuel or spark as a result. The engine is mechanically capable of running and is being deliberately prevented. Causes include a degraded transponder chip, a failed antenna ring around the ignition, or a relearn that was never completed after a repair.

Does replacing an ignition cylinder require reprogramming the key?

On many platforms yes. Some vehicles tie the immobilizer to the ignition assembly, so once the cylinder or module is changed the system needs a relearn procedure before it will accept any key. As of August 2026 that relearn typically adds about $80 to $170 to the job in Arlington.

How do I know whether to call a locksmith or a mechanic?

Use the crank as the divider. Strong crank with no start plus a security telltale is a key, immobilizer or programming issue and a locksmith resolves it. No crank at all, or a slow lazy crank, points at battery, starter, ground or supply and a mechanic resolves it. Calling the wrong one costs a trip charge and a day.

Can a locksmith diagnose a no-start that isn't key-related?

A good one can tell you it is not key-related, which is the valuable part. Reading whether the immobilizer is accepting the credential is a definitive test, and if it is accepting the key then the fault is downstream in fuel, spark, compression or starting circuit, and we say so rather than selling you a key you do not need.

Could a new key be the problem rather than the fix?

Occasionally. An aftermarket key with a mismatched or counterfeit chip can program successfully and then behave intermittently, working on warm days and failing on cold ones. If a no-start began within weeks of a cheap replacement key, testing with a known-good key is one of the fastest diagnostics available.

Will the vehicle need towing to fix a no-start?

Not if the fault is in the key, the immobilizer or the ignition assembly — all of that is mobile work done where the vehicle sits. Towing becomes necessary when the diagnosis lands on internal engine, fuel-delivery or major electrical faults that require a lift and a shop.

Find out which fault you actually have

A no-start after an ignition repair is frustrating precisely because the obvious explanation has already been ruled out. Arlington TX Locksmith reads whether your immobilizer is accepting the key, completes the relearn if that is what is missing, and tells you honestly when the answer lies with a mechanic instead.

Call or text (817) 330-5762 with your year, make, and whether the engine cranks. You can also reach us through our contact page, read more about our mobile service, or see what a mobile call includes.

Arlington TX Locksmith — 24/7 mobile automotive locksmith service across Arlington and Tarrant County. Texas locksmiths are regulated by the Texas Department of Public Safety Private Security Program.

Ignition Fixed But the Car Still Won't Start — Arlington TX Guide