UF822 Ignition Coil (4-Pack) for 2017–2018 Toyota Yaris iA & 2016 Scion iA 1.5L – 2026 Buyer's Guide & Technical Review
Why Your 2016–2018 Scion iA / Toyota Yaris iA Deserves a Premium Ignition Coil Upgrade in 2026
The UF822 ignition coil is the heartbeat of the 1.5L SkyActiv-G engine found in the 2017–2018 Toyota Yaris iA and 2016 Scion iA. As these vehicles age into the 7–10 year window, original coil-on-plug (COP) units degrade from sustained thermal cycling, voltage stress, and under-hood contamination. In 2026, with the global aftermarket ignition coil sector projected to surpass $6.8 billion and COP technology commanding over 70% of OEM installations, choosing a precision-engineered replacement like the 4-Pack UF822 Ignition Coil from Koeep is not just maintenance — it's a strategic investment in drivability, fuel economy, and emissions compliance.
The Yaris iA / Scion iA platform — a Mazda2-derived compact sedan — relies on a high-compression 1.5L L4 mill that demands precise spark delivery across all four cylinders. Even a single marginal coil can trigger cascade misfires, increased hydrocarbon emissions, and catalytic converter stress. Replacing all four coils as a matched set restores factory-spec ignition performance and ensures balanced cylinder firing.
UF822 Ignition Coil — Key Product Highlights
- Coil-On-Plug (COP) Architecture: Eliminates traditional spark plug wires, reducing RF interference and energy loss — aligned with 2026 OEM COP-dominant design standards.
- 3-Pin Precision Connector: Direct plug-and-play fitment matching the OEM harness on all 2017–2018 Yaris iA, 2016 Scion iA, and select 2019–2020 Yaris 1.5L models.
- High-Temp Epoxy Encapsulation: Proprietary vacuum-filled epoxy resin protects internal windings against moisture ingress, vibration fatigue, and thermal shock — critical for engines operating at compression ratios exceeding 13:1.
- Matched 4-Pack Configuration: Individually tested for primary/secondary resistance tolerance within ±3%, ensuring uniform spark energy across all cylinders.
- 2026-Ready Materials: Copper-core primary windings with silicone-steel laminate E-core lamination stacks, meeting evolving aftermarket durability benchmarks.
Technical Specifications & Vehicle Fitment
| Specification | Detail |
|---|---|
| Part Number | UF822 (4-Pack Set) |
| Coil Type | Coil-On-Plug (COP) / Pencil-Type |
| Connector Pins | 3-Pin (OEM-Grade Harness Interface) |
| Primary Resistance | 0.5 – 0.9 Ω (Typical at 20°C) |
| Secondary Resistance | 8.5 – 11.5 kΩ (Typical at 20°C) |
| Encapsulation Material | Vacuum-Poured High-Dielectric Epoxy Resin |
| Compatible Vehicles | 2017–2018 Toyota Yaris iA 1.5L | 2016 Scion iA 1.5L |
| Additional Cross-Fit | 2019–2020 Toyota Yaris 1.5L (Non-Hybrid, Verify 3-Pin) |
| Engine Platform | Mazda SkyActiv-G 1.5L L4 (P5-VPS / 1,496 cc) |
2026 Diagnostic Insights: DTC Fault Codes & Failure Symptoms
When a UF822 coil begins to degrade — or when the original OEM unit has reached end-of-life — the ECU stores specific fault codes. Here are the most frequently encountered Diagnostic Trouble Codes (DTCs) on these Mazda-derived platforms:
| DTC Code | Description | Likely Cause |
|---|---|---|
| P0300 | Random/Multiple Cylinder Misfire Detected | Widespread coil degradation; replace full set of 4 |
| P0301 – P0304 | Cylinder 1–4 Misfire Detected | Isolated coil failure on specific cylinder |
| P0351 – P0354 | Ignition Coil 'A'–'D' Primary/Secondary Circuit | Open or short in coil windings; internal breakdown |
| P0350 | Ignition Coil Primary/Secondary Circuit Malfunction | Generic circuit fault; verify harness and coil assembly |
| P2300 – P2304 | Ignition Coil 'A'–'D' Primary Control Circuit Low | ECU driver circuit fault or coil primary short |
⚠ Important: Do not replace a single coil in isolation on a 7+ year-old vehicle. Mismatched coil aging profiles cause uneven spark energy, leading to persistent misfire codes and potential catalytic converter damage. The UF822 4-pack from Koeep ensures all cylinders receive factory-balanced ignition energy.
Why Aftermarket UF822 Coils Excel in 2026's Evolving Standards
The 2026 ignition coil aftermarket is shaped by three macro trends: stricter global emissions regulations requiring cleaner combustion, higher compression ratio engines demanding greater spark voltage stability, and extended vehicle ownership cycles pushing average fleet age past 12 years. The UF822 addresses all three:
- Emissions Compliance: Consistent spark energy reduces unburned hydrocarbon (HC) output during cold-start and WOT conditions, helping your Yaris iA or Scion iA meet state I/M inspection standards in 2026.
- High-Compression Compatibility: The SkyActiv-G's 13:1 compression ratio (North American tune) demands a dielectric breakdown threshold well above 35 kV. The UF822's epoxy encapsulation and optimized winding geometry provide a stable 40+ kV output ceiling.
- Longevity Matching: With average vehicle retention now exceeding 8 years, a matched 4-coil set eliminates the "whack-a-mole" replacement cycle that plagues single-coil repairs.
Installation Notes & Best Practices (2026 Updated)
Replacing the ignition coils on the 1.5L SkyActiv-G engine is a straightforward DIY procedure. Note these 2026 best-practice recommendations:
- Disconnect the negative battery terminal before beginning work to protect the ECU from voltage transients.
- Remove the engine beauty cover (if equipped) to access all four COP units along the valve cover.
- Replace spark plugs concurrently — worn plugs increase coil dwell time and accelerate new coil degradation. NGK Laser Iridium or Denso Iridium TT plugs are the OEM-recommended match for this engine.
- Apply dielectric grease sparingly to the coil boot interior (not the electrical connector pins) to prevent moisture intrusion without compromising conductivity.
- Clear all stored DTCs post-installation and perform an idle relearn procedure to reset fuel trim adaptations.
Frequently Asked Questions
Are the UF822 coils compatible with the 2019–2020 Toyota Yaris (non-iA)?
Yes, with verification. The 2019–2020 Toyota Yaris 1.5L (non-hybrid, Mazda-derived hatchback) shares the same SkyActiv-G engine platform and 3-pin COP connector. Always visually confirm the 3-pin harness before ordering. The UF822 set is a direct fit for the 2017–2018 Yaris iA and 2016 Scion iA without modification.
What are the symptoms of a failing ignition coil on the Scion iA / Yaris iA?
Key indicators include: rough idle with visible tachometer fluctuation, hesitation or stumbling under acceleration (especially at 2,000–3,500 RPM), a flashing check engine light during misfire events, reduced fuel economy (typically 10–25% drop), and a raw fuel odor from the exhaust indicating incomplete combustion. Any persistent P0300-series DTC warrants immediate coil inspection.
How do UF822 coils compare to OEM Mazda / Toyota parts?
The UF822 is an aftermarket direct replacement engineered to meet or exceed OEM specifications for primary/secondary resistance, spark energy output, and thermal endurance. While OEM coils from Mazda (PE01-18-100 family) and Toyota are manufactured to factory tolerances, high-quality aftermarket units like the Koeep UF822 4-pack offer equivalent performance at a significantly more accessible price point — a critical advantage when replacing all four coils as a matched set.
Should I replace all four ignition coils at once?
Absolutely. These engines use a waste-spark-free COP system where each cylinder's coil operates independently but ages at a near-identical rate under the same thermal and electrical stress. Replacing only the failed coil creates an imbalance: the new coil delivers stronger spark than the three aged units, potentially masking intermittent misfires on those cylinders until they fail catastrophically. A matched 4-pack replacement is the only service strategy recommended by diagnostic professionals in 2026.
What is the expected service life of UF822 coils under normal driving conditions?
Under normal driving conditions (12,000–15,000 miles/year, regular maintenance), the UF822 coil set is engineered for a service life of 80,000–100,000 miles. Contributing factors include spark plug condition (worn plugs shorten coil life), driving environment (extreme heat accelerates epoxy aging), and the use of quality fuel (excessive ethanol content increases combustion chamber temperatures). Concurrent spark plug replacement is strongly recommended to maximize coil longevity.
🛒 View the UF822 4-Pack Ignition Coil on Koeep — Restore Peak Ignition Performance Today