Jaguar S-Type Won't Start, No Crank
Before buying anything, watch the red security lamp by the screen at key position II: on for two seconds then out means the key was accepted and the fault is in the starting circuit; flashing means the car is refusing the key. In the starting circuit the answers are often cheap — a loose relay, a dirty key, a flat battery — with one expensive trap: a new starter built to turn the wrong way.
How bad is it · Safe to drive
The car stays put — nothing gets worse while you diagnose
None of these faults damages the car further; the risk is buying starters, batteries and modules on a guess. The security system can refuse the key only when cold — note when it happens, it narrows the search.
Which one applies to yours depends on your symptoms, your model year and what has already been done to it.
Likely causes, most common first
Read the check cost before the odds: a free check that rules a cause out beats a likely guess that costs money.
A relay in the engine-bay box not fully seated
The key doesn't feed the starter directly; it energises a relay in the engine-bay box. A relay that has worked loose clicks and still breaks the circuit.
Everything electrical works, key accepted, battery charged — a click from the engine bay, no crank.
Open the box, press every relay firmly home, and make sure none rocks in its socket. The same box holds two powertrain control relays; a failing relay goes from intermittent to permanent, so reseat them all, not just the starter relay.
Push the loose relay home; the front box is on the left of the car.
Dirty contacts or a worn key
The key carries the chip the car reads, and key and lock must make good contact for the start request. Dirt or wear can make the car act as if the battery were dying.
At START the dash dims as if the battery were low, though it's good; a few tries and a wiggle of the selector sometimes get it going.
Clean the key blade and try the spare.
Clean the key.
Low voltage: a flat battery or a poor connection
Panel lamps dimming under the starter's load mean voltage is being lost: a tired battery, or a poor connection on the live or earth side. The main cable runs from the boot battery past the alternator to the starter, and faults at the alternator end are a common cause.
Dash dims or dies at START with a click — or a car fine yesterday is dead this morning. An intermittent no-start that comes with ABS, park brake and DSC warnings all at once, on a good battery, points to an earth rather than to any of those systems.
Charge or jump first. Then the battery clamps, the body earth strap, and the heavy cable at the alternator and starter. Most dash lamps going dark at START is normal on this car. The engine earth is easy to miss: nothing shows on a test drive and no codes are stored. A battery that still takes a charge can be too tired for this car's electronics.
Charge or jump, and clean or tighten the bad connection. A car cover can hide exit lamps left on overnight. On a 2002 car with that pattern, removing the engine earth nut, cleaning both faces and refitting it with new washers ended the no-starts.
The starter — even a brand-new one
Starters do fail. But a cheap replacement can be built for the wrong rotation: it spins on its one-way clutch and never turns the engine.
A new starter spins fast and loud and the engine doesn't turn; or a single click, then grinding on later tries. A high-pitched whine like a drill means the pinion isn't reaching the flywheel. Cranking that is suddenly far too easy and fast is a different matter: on a V8 it points at the timing chain, so turn the crank by hand and see whether the camshafts follow.
Run a replacement on the bench and compare its direction with the old one. Feeding the solenoid directly proves whether the starter is the problem at all.
A new starter of the correct rotation. The starter is held by three nuts on studs, the top one out of sight; the solenoid cables, an oxygen sensor and its plug, an earth cable and a harness retainer come off first, and a deep socket is needed.
The security system refusing the key
The instrument pack runs the immobiliser. If it doesn't accept the key, it won't let the starter relay work, and fuel and spark are blocked too.
The security lamp flashes instead of going out after two seconds; after a minute it flashes a countable two-digit code. A remote that locks and unlocks the car but won't let it crank is the classic sign of a key the car doesn't recognise.
Key to II, wait a minute, count the code. A refused key isn't always the key: a harness plug backed out on the bulkhead, or a weak battery, can do it. The immobiliser can't be switched off, and a flat battery doesn't erase keys. A new key or a new lock barrel must be registered with the car, which needs dealer-level software and a second working key.
Worth checking the plug on the inside of the bulkhead by the main junction box — with broken locking tabs it can half come out and take a data network with it (code 16). A 2006 key that did everything except crank was cured by reprogramming at a dealer; a 2000 car with a Theft Detected message only was reset by the dealer. An independent specialist can pair new keys for roughly £45–60. Don't swap modules to cure a key problem: the vehicle identity is shared between them, and a borrowed module can leave a car that no key will start.
Relay control: Park/Neutral feed, instrument-pack earth
The starter relay coil is fed through the Park/Neutral switch and earthed by the instrument pack only when security is satisfied. A fault on either side stops the crank with a good starter.
Bridging the relay's power terminals cranks and starts it at once. It may fail only when cold. The commonest reason for a dead starter with a good key is the selector switch not reporting Park.
Try P then N, wiggle the selector. With the fault present and the key held at START, measure both coil terminals: no feed on one side means the fuse or Park/Neutral switch; feed on both means the pack isn't earthing it. The immobiliser works by cutting the earth side of the starter relay, so a refused key and a relay-control fault look alike at the relay.
No proven cure yet — but if bridging the relay starts it, the starter is fine and the fault is on the relay's control side.
The order to check them in
The point of the order is money: each step either rules a cause out or makes the next one worth doing. Green is free, amber costs a little, red is the one to arrive at last.
Key to II: watch the security lamp
On two seconds then out: key accepted, carry on here. Flashing: count the code after a minute.
freeCharge or jump the battery
A dash that dims at START is voltage being lost.
freeTry Neutral; clean the key; try the spare
Wiggle the selector in Park too.
freePress every relay home in the engine-bay box
A loose starter relay clicks and still breaks the circuit.
freeCheck the heavy cable and the earths
Battery clamps, body earth, the cable at the alternator and starter.
freeProve the starter before replacing it
Bridge the relay or feed the solenoid, car in Park. If it cranks, the starter is fine.
freeReplacement starter? Check its rotation on the bench
Compare with the old unit before it goes in.
a starterThe fuses named above — where they sit
The highlighted position is the one the procedure talks about. Pulling a fuse is a stop-gap, never a repair: check what the circuit feeds before you pull it.
Circuit descriptions from the Jaguar handbook, 2007 edition, p. 6, 7. Drawing by jagaux.com from the factory electrical guide. Fuse layouts change between model years — read the legend on the lid of your own box before pulling anything.
Circuit descriptions from the Jaguar handbook, 2007 edition, p. 9, 10. Drawing by jagaux.com from the factory electrical guide. Fuse layouts change between model years — read the legend on the lid of your own box before pulling anything.
These positions are not on the drawings above — find them on the legend printed on the lid of the box itself.
What it usually isn't
Don't spend money here first:
If none of this finds it:
On jagaux.com
- Jaguar S-Type Battery Drain, Battery Flat OvernightIf the battery keeps going flat while parked.
- S-Type fuse and relay boxes, 2002Where the starter relay sits on your year — other years from the same page.
- Jaguar VIN decoderConfirm your exact model year, engine and factory options before ordering parts — free.
Ratings, fuse numbers and torque figures vary by model year and market. Read the legend on your own car before pulling anything, and use the figures in the manual for your car, not the ones in a video.
Check your VIN: exactly which car you have and which bulletins apply to it.