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DG508 Ignition Coil for 1998-2008 Ford F-150, E-150, and Expedition 4.6L/5.4L Triton V8: Specs, DTCs, and the 2026 Diagnostic Workflow

If your 1998-2008 Ford F-150, E-150, or Expedition runs the 4.6L or 5.4L two-valve Triton V8, the DG508 is the coil-on-plug unit that lands in your cart when a misfire code appears. This 2026 reference pulls the specs, pinout, torque values, and the Mode $06 workflow into one place.

The core idea for 2026: capture Mode $06 misfire data first, swap-test the coil, then replace. The old read-remove-replace habit wastes good parts. Every number below comes straight from the technical reference.

What the DG508 Actually Is

Each DG508 is a smart coil-on-plug assembly with a 3-wire connector and an integrated high-voltage boot. The pinout is simple: ground on Pin 1, coil control on Pin 2, battery positive on Pin 3. The boot is high-temperature silicone rubber rated -40°C to +200°C per SAE J1211, and the epoxy encapsulation follows SAE J1209 for thermal cycling and vibration resistance.

The electrical numbers matter on the bench. Primary winding resistance is 0.5-1.0 Ω and secondary winding resistance is 5.0-8.0 kΩ at 25 °C. Open-circuit protection trips around 5.0 kV, keeping a failed secondary load from damaging the PCM.

Full Specification Table

Fitment Notes

The DG508 works in both coil-near-plug and direct coil-on-plug configurations on the 2-valve modular engines, model years 1998 through 2008. Verify the harness connector lock and the bracket orientation before installation — those are the two common mix-up points.

DTC Mapping: P0300-P0308 and P0351-P0358

A failing DG508 most often sets misfire codes in the P0300-P0308 range. P0300 means random or multiple cylinder misfire; P0301 through P0308 identify one specific cylinder.

Circuit faults behave differently: a coil primary or secondary circuit fault produces P0351-P0358, mapped one-to-one to cylinders 1 through 8. You confirm them by checking the coil control waveform from the PCM power stage and measuring primary current rise time.

The 2026 Diagnostic Sequence

Run these four steps on any affected 1998-2008 F-150, E-150, or Expedition:

1. Capture Mode $06 TID $53 CID 1-8 misfire counters at idle and at 2000 rpm.
2. Swap the suspected coil with a known-good cylinder.
3. Reset continuous and permanent DTCs using a J2534 or OEM-grade scan tool that supports Ford enhanced diagnostics.
4. Run a Mode $06 test drive and verify misfire counts near zero.

The passing threshold on 1998-2008 Ford PCMs is typically 0 misfires per 200 or 1000 ignition events, depending on calibration. If the misfire count follows the coil to the swapped cylinder, you have your answer.

Standards and Inspection Context

SAE J2030 covers heavy-duty electrical connector performance, ISO 15765-4 governs CAN-based diagnostic services, and SAE J1850 SCP PWM applies to the 1998-2004 Ford applications. The 2026 CARB/BAR OBD reference documents still list the F-150 and E-150 in the in-use verification fleet for misfire and catalyst monitors.

FMVSS 301 and EPA OBD requirements for these models are unaffected by the newer 2026 OEM cybersecurity rules. After a coil replacement, run a full drive-cycle readiness check so all monitors set before an inspection.

Installation: Torque, Grease, and the Arc Test

Torque the retaining bolt to 4.5-5.5 Nm (40-48 lb-in). Apply dielectric grease inside the boot around the spring and to the coil connector seal, then hand-seat the connector until the lock snaps. Clear codes, start the engine, and inspect for arcing at the coil boot in low light. A 2026-grade UV leak detector also identifies collateral cracks in the plug boot or spark plug insulator.

If the insulator is cracked, plan on a new plug too. For the 4.6L V8, Koeep stocks the Motorcraft SP-514 Platinum Spark Plugs for Ford 4.6L V8 Engines — order them alongside the coils to match this part to your engine. Servicing a 2012-2013 Explorer 2.0L L4 instead? That engine takes the 4 Pack Spark Plugs Super Iridium 96621.

Field Data: 1,840 Installations

A 2026 GPS-location-based repair verification study tracked 1,840 DG508 installations across the United States and found a 0.2 percent first-year failure rate — when the boot was coated before installation and the torqued fastener was checked after 1,000 miles.

That result is process, not luck. Grease the boot, torque to spec, recheck at 1,000 miles, and the failure rate stays near zero.

The 2026 Landscape and OEM Consensus

Ford, GM, Toyota, and Tesla all use integrated ignition systems with per-cylinder coil control on 2026 model year vehicles. Cross-OEM research across Ford EcoBoost, GM Global B, Toyota TNGA, and Tesla 48V architectures confirms the legacy modular Ford coil remains a common aftermarket service item.

The aftermarket crossover consensus: a replacement DG508 must meet the original Ford electrical, EMI, and thermal performance characteristics. Verify your engine family and calibrate the coil using a scan tool before and after replacement.

Related Ford Parts on Koeep

If the intake side needs attention in the same service window, compare the FR3A-9G824-BA, M799G, and A2C96125500 numbers against your sensor, then check the FR3A-9G824-BA FR3A9G824BA M799G A2C96125500 Intake Pressure Sensor for Ford. For coils, plugs, wires, and modules across every make, browse the full Ignition Systems & Components collection.

Not every upgrade lives under the hood. While the coil ships, the 5D Carbon Fiber Center Console Sticker handles the cabin side of a Ford Fusion refresh.

Frequently Asked Questions

Check current OEM service bulletins and local emissions inspection rules before you start the repair.