Parts for your 1999 Toyota Crown-Ignition coils

1999 Toyota Crown ignition coils — what they do and when to replace them

Based on the Toyota Crown (S170, 1999) Repair Manual, the Toyota Electronic Parts Catalogue for JZS17#/GS171/LS171 models, and the DENSO aftermarket ignition catalogue, all 1999 Crown inline‑six petrol engines (1G‑FE, 1JZ‑FSE, 2JZ‑GE/2JZ‑FSE) use direct ignition with coil‑on‑plug units. So yes, ignition coils are fitted to the 1999 Toyota Crown and are directly relevant to servicing.

On this Crown, each ignition coil sits on top of a spark plug and transforms the 12‑volt supply into the high voltage needed to jump the plug gap. Coil‑on‑plug keeps the spark strong and precise, helping with smooth idle, crisp throttle response, and better fuel economy compared with old distributor setups. It also cuts down on leads and high‑tension losses — handy on long‑life iridium plug intervals common to these engines.

Coils aren’t strict “service items”, but age, heat, and oil in the plug tubes can tire them out. Typical signs include a rough idle, stumble under load, hard starting, a flashing MIL, or codes like P0300–P0306. On the D‑4 direct‑injection variants (1JZ‑FSE/2JZ‑FSE), a lazy coil can feel like a fuelling issue, so proper diagnosis matters.

Good workshop practice for a 1999 Toyota Crown:

• Inspect coil boots and plug wells every 40,000–60,000 km, fix rocker cover leaks that let oil sit around the coils.
• When replacing spark plugs (typically 100,000 km+ for iridium), check coil connectors for brittleness and corrosion, a light smear of dielectric grease on the boot lip can help sealing.
• If one coil fails, it’s fine to replace just that unit with quality OEM‑equivalent (DENSO is the factory supplier). Keep spares on hand for touring.
• Torque the coil hold‑down bolts correctly (about finger‑tight plus a nip — roughly 8–10 N·m) and don’t pinch the loom.
• After replacement, clear fault codes and road test, a smooth idle and clean pull from low revs are the giveaways it’s sorted.

Many S170 Crowns run original coils well past 150,000 km, but once heat cycling takes its toll, failures often arrive one after another. For owners chasing rock‑solid reliability, refreshing ageing coils at the same time as plugs can save repeat trips back under the bonnet.

Popular questions about 1999 Toyota Crown ignition coils

How many ignition coils does a 1999 Toyota Crown have?
Most 1999 Crowns run inline‑six engines with one coil per cylinder, so there are six coils in total. Engine codes like 1G‑FE, 1JZ‑FSE, and 2JZ‑GE/2JZ‑FSE in the S170 series are all coil‑on‑plug designs.

Is it safe to drive with a misfiring coil?
It’ll usually still run, but it’s not a great idea. A persistent misfire dumps unburnt fuel into the exhaust, which can overheat and damage the catalytic converter and O2 sensors, and it’ll chew through fuel. Best to sort the coil promptly.

Which ignition coil brand should be used?
Stick with OEM‑quality coils that match the engine code — DENSO is the factory supplier on these cars and a safe bet. Avoid no‑name bargains, inconsistent output can create hard‑to‑trace misfires. It’s fine to replace a single failed coil as long as the spec matches the others.