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2004 Dodge Ram 2500 Hemi 5.7 Lifting P2302 Secondary Ignition Code After Plug, Wire, and Coil Replacement

Model: 2004 Dodge Ram 2500 Hemi 5.7 Fault Code: P2302 Posted: 2018-02-11 11:19

My 2004 Dodge Ram 2500 Hemi 5.7 is showing a persistent P2302 code (Secondary Ignition System) even after replacing all ignition components — spark plugs, ignition wires, and all four coils. I've cleared the code using two different OBD2 apps and at AutoZone, but the check engine light still flashes for one second immediately after starting the engine. The truck is stock with no aftermarket modifications such as tuning chips or performance parts. There are no other diagnostic codes present. I replaced the spark plugs with Champion iridium, ignition wires with high-quality RockAuto brand, and all four coils (including swapping each coil to test for consistency) — all completed three days ago. The issue has been present since I purchased the truck in September, and it currently has 61,000 miles. I'm now considering that the problem may lie in wiring or connector integrity. Specifically, I want to verify if there's a short or corrosion at the coil connectors or along the wiring harness near the #2 coil. Could a damaged ignition module or PCM driver be responsible? Any guidance on how to perform voltage checks using a multimeter would be greatly appreciated.

Related fault codes
P2302
Comments (6)
Anonymous 2018-02-11 11:22

2004 Dodge Ram 2500 Hemi 5.7 - stock configuration, no aftermarket tuning or modifications.

Anonymous 2018-02-11 12:20

You cannot clear the code if the underlying issue persists — the system detects it immediately. This vehicle is stock with no chips, tuners, or aftermarket parts? Are there any other diagnostic codes? The P2302 code specifically indicates a voltage pattern fault in the #2 coil's secondary circuit. Did you use the correct spark plugs? The owner’s manual recommends Champion copper plugs for this model. Ignition wires — ensure they are high-quality, not store-brand. Coils: Try swapping the #2 coil with an easily accessible one (e.g., #1 or #4) to see if the code moves. This helps isolate whether it's a coil issue or wiring. Wiring connections: Check that the coil connector is tight and free of corrosion. Inspect the wires within 6 inches of the coil — this area is most prone to failure. A compression test may also be helpful in ruling out internal engine problems.

Anonymous 2018-02-11 12:31

Thanks for the reply! Yes, it's a stock truck with no modifications. No other codes are present. I replaced all four coils three days ago using high-quality Red Top coils from RockAuto. Plugs are Champion iridium — confirmed per owner’s manual. Wires were also upgraded to premium RockAuto quality. All changes were completed 3 days ago, and the issue has been ongoing since I bought the truck in September (61,000 miles). I swapped all four coils (1 through 4) for testing — the P2302 code remains unchanged. I haven't yet inspected the wiring or connectors. Is that likely the root cause? Thanks again!

Anonymous 2018-02-11 18:43

Check the wiring and electrical connections, especially at the coil connector. A shorted coil could have damaged the PCM driver circuit. Do you have a multimeter and test probes available? You can perform voltage checks at both the coil terminals and the PCM connector. A test light is also recommended for continuity testing. Is this a COP (Coil-On-Plug) system or a traditional distributor setup?

Anonymous 2018-02-11 18:48

Yes, I have a multimeter and a test light. This is a COP (Coil-On-Plug) system.

Anonymous 2018-02-11 18:56

What voltage readings should I expect when testing the connections with a multimeter? Specifically: 12V on the primary side when starting the engine, and a pulsing or varying voltage pattern on the secondary side as detected by the PCM?