Fiat 500L Spark Plugs: Intervals, Fitment & Warning Signs
On the 500L, if TwinAir, even after replacing a faulty coil the ECU can genuinely stay stuck in a reduced-power mode until fault memory is properly cleared.
Illustration for editorial purposes
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OEM Part Number: confirm via engine code — aftermarket NGK 6046 / Bosch 0 242 135 515
| Petrol engines in this generation | 0.9 105 HP (199LYC1B), 1.4 95 HP (199LYB1B), 1.4 120 HP (199LYF1B), 1.4 127 HP, 1.4 160 HP, 1.4 162 HP; 0.9 Natural Power CNG and 1.4 LPG also listed |
|---|---|
| Spark plugs (aftermarket) | NGK 6046 (iridium, 5 kOhm, M12x1.25, 16 mm, thread 19 mm); NGK 93311 (iridium, SAE connector, 19 mm thread); NGK 97168 (iridium, 26.5 mm thread); NGK 4983 and 94037 (nickel); Bosch 0 242 135 515 (gap 1.0 mm); Bosch 0 242 140 519 (gap 0.7 mm); Bosch 0 242 140 514 (gap 0.7 mm); Denso IXU22FTT (iridium, platinum earth) |
| Genuine (OE) numbers quoted | Denso XU22TT = 1WT418110; Denso IXU27 = 55210685; Denso XU22EPR-U = 55188857 |
| Fitment notes | All plugs are the 16 mm hex M12x1.25 family (Ridex 686S0043 is 14 mm), in 19 mm and 26.5 mm reach versions. NGK 6806 is the CNG/LPG plug with a 60,000 km interval. |
A Genuinely Important Technical Fact Worth Knowing on TwinAir Models — Fiat 500L Spark Plugs
If you've replaced a faulty ignition coil on the TwinAir engine but the car still feels down on power, this is genuinely worth knowing: when a coil fails, the ECU logs misfire faults and can drop into a catalyst-protection limp mode. Even after the coil has been correctly replaced, the ECU can remain in this reduced-power state until the fault memory has been properly cleared using the correct diagnostic equipment — cheap, generic OBD readers often can't display or clear these specific fault codes.
It's also genuinely worth knowing a useful UK consumer rights point: a persistent, unresolved misfire that a dealer fails to properly diagnose after multiple attempts, particularly on a recently purchased car, can potentially be sufficient grounds for rejecting the car entirely under UK consumer protection law.
Fiat 500L Spark Plugs: A Cheap Part That Causes Expensive-Feeling Problems
On the Fiat 500L, symptoms of worn spark plugs are subtle by nature — a touch rougher at idle, a little less responsive off the line — and easy to attribute to almost any other engine gremlin. Because the part itself is so cheap, it's routinely overlooked well past when it should've been changed.
Fiat 500L Spark Plugs: Watch: Replacing It
Names 500L; US-oriented 1.4 turbo
Fiat 500L Spark Plugs: What They Do
How well the Fiat 500L's engine runs, how efficiently it burns fuel, and how smooth it feels are all tied to spark plug condition, since these ignite the compressed fuel-air mixture in each cylinder. That's a petrol-engine job specifically — diesels ignite fuel through compression and have no spark plugs at all.
Fiat 500L Spark Plugs: Generations & Spark Plug Count
| Diesel variants | Not applicable — diesel engines use compression ignition and have no spark plugs at all |
|---|---|
| Petrol variants (all trims) | 4 spark plugs — one per cylinder |
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Fiat 500L Spark Plugs: Warning Signs, DIY Difficulty & Aftermarket Advice
These are the same regardless of make or model — see our full Spark Plugs Guide for symptoms of worn plugs, why matching your exact plug specification matters, and trusted brands to buy from.
More Fiat Spark Plugs
The same part, covered across other Fiat models.